;; Part One

;; #+NAME: day8-imports

;; [[file:chicken-src.org::day8-imports][day8-imports]]
;; -*- geiser-scheme-implementation: chicken -*-
(import (chicken irregex)
        (chicken sort)
        (chicken string)
        (chicken type)
        (chicken format))
;; day8-imports ends here



;; #+NAME: day8-input-scm

;; [[file:chicken-src.org::day8-input-scm][day8-input-scm]]
;; -*- geiser-scheme-implementation: chicken -*-
(define input "
  LRRLRRRLRLRLLRRLRLRLLRLRLRLLLLRRRLLRRRLRRRLRRRLLRLLRLRRLRLRLRRRLLLLRRLRLRRLRRLLRRRLRRLRLRRLRRLRRLRRLRLLRRLRRLLLLRLRLRRLLRRLLRRLRLLRLRRLRRLRRLRRRLRRLLLRRLRRRLRLRRRLLRLRRLRRRLRRLLRRRLRRLRLLRRLLRRLRRLRRRLRRLLRRLRRRLRLRLRLRLRLRRLRRLLRRRLRLRRLRRRLRLRLRLRLRLRRRLRRLRRRLLRRLRLLRRRLRRLRLLLLRRRLRRLRRRR
  
  DRM = (DLQ, BGR)
  PKD = (TNC, DKH)
  FSM = (LKS, KPG)
  NDS = (KGD, HNX)
  KQQ = (DPF, GKD)
  SBX = (DDL, MGH)
  GCV = (KMG, GLP)
  PCT = (JXN, XDR)
  KHR = (QPK, FPQ)
  FCK = (GLS, GGP)
  MKR = (XPQ, TJX)
  PFP = (RPR, LPS)
  XPC = (SSS, FRX)
  PTJ = (LSC, CND)
  GVJ = (NRL, SHV)
  QNF = (MBQ, GSR)
  TMK = (DVM, BJM)
  KTG = (QVG, LLX)
  JMK = (BKF, XDK)
  JQV = (DCM, RLT)
  VFH = (FDD, GML)
  XPN = (FKG, CXG)
  GDX = (GRV, BPP)
  GVP = (JLP, XNJ)
  TCB = (RVR, QXQ)
  DLP = (XDK, BKF)
  FQG = (RMH, QHR)
  XDD = (SMK, HMN)
  TLL = (TVV, FXX)
  NPT = (NGC, FQM)
  XQK = (PQG, QTK)
  DMQ = (RVS, KNQ)
  QKR = (SJD, PLH)
  XNV = (SJB, GCV)
  SRP = (CDK, JFK)
  FRP = (FFD, XPC)
  PVC = (XVD, MGD)
  DPP = (BFQ, XDD)
  CNV = (LQC, JJH)
  LLH = (CFP, BGF)
  XCK = (VDX, GFC)
  KGD = (LSF, FNK)
  MJA = (FXB, QVX)
  QLH = (KRM, KVD)
  QCR = (TKN, RNB)
  PSR = (FBL, HKJ)
  MGK = (BVC, HVL)
  PVK = (JRN, SMV)
  JTD = (VNS, FGJ)
  PMD = (HGN, NBM)
  DRF = (CPR, RTX)
  HJL = (CBR, VDR)
  PPB = (GDX, DXB)
  DVR = (LLT, GVJ)
  JRN = (RLD, RSL)
  NXM = (RBN, NVD)
  RLV = (FRM, FJB)
  SJB = (KMG, GLP)
  KJM = (XJH, LQX)
  GRB = (HHL, RGD)
  LQC = (BMC, XSH)
  NRB = (NQD, RFT)
  SQH = (QJT, JXX)
  JLX = (RJL, HHH)
  HVR = (XPN, JFM)
  FVD = (RXS, RHH)
  KSX = (TCB, GDK)
  GKJ = (TQF, HQJ)
  HQL = (BMR, PBX)
  QFP = (NJM, FSB)
  TPH = (NXT, RKN)
  SRL = (LSP, LFV)
  SDL = (MGL, PSK)
  MFX = (FSM, LQF)
  RFT = (FLV, GMS)
  BTG = (DRS, PVC)
  HLR = (DSB, DPP)
  DXB = (BPP, GRV)
  NHS = (HQG, GVP)
  GKK = (DCM, RLT)
  MJT = (JNR, PGC)
  KDS = (FFD, XPC)
  TSS = (BGX, QQX)
  FKC = (NBN, SJP)
  HHQ = (GVP, HQG)
  JKF = (QRR, GFD)
  CXG = (SDD, TMN)
  GCG = (TCC, TDT)
  NQX = (DMQ, DPM)
  GHX = (BJQ, CHJ)
  JQC = (HNQ, RJF)
  QBB = (GNH, XSC)
  BJG = (VMH, FCN)
  VMS = (KRX, VLQ)
  GSF = (NQM, KBH)
  JQQ = (PKD, GNB)
  KFG = (BGX, QQX)
  TTV = (SNB, JQF)
  CXJ = (CND, LSC)
  GGP = (PBH, XNG)
  FCV = (NLP, QJK)
  NSB = (KSX, SLL)
  JBH = (RGK, NSS)
  CQH = (HJL, FKR)
  VRX = (HKJ, FBL)
  HJZ = (QVX, FXB)
  RLD = (BJP, RLV)
  HHH = (PNJ, HPJ)
  LSC = (NRP, DCF)
  BVM = (RCG, QLL)
  KGN = (PRB, MLT)
  NTV = (MRQ, NHQ)
  VXT = (VFH, MBX)
  RLG = (MJQ, RNL)
  JVX = (HJQ, FNV)
  XGH = (HHK, JXT)
  NHC = (HPX, LGG)
  VPC = (XCL, HPQ)
  HKJ = (RQC, TMK)
  PGQ = (FTX, MNP)
  MPF = (KNM, BJG)
  MFT = (DRS, PVC)
  XNG = (RCS, JNH)
  RMH = (GHD, MPF)
  PFM = (PGQ, XHJ)
  TRN = (TCP, TCP)
  NHP = (JMG, VGP)
  JSK = (JBG, PVM)
  FSB = (MGK, HTD)
  BPR = (VFH, MBX)
  RHM = (LHD, PTF)
  PRV = (RJL, HHH)
  GNC = (HVR, PSV)
  PSV = (JFM, XPN)
  KMG = (KDR, RTV)
  RKL = (DPP, DSB)
  GLN = (QJT, JXX)
  FNK = (XXP, QDR)
  JDP = (HVR, PSV)
  HHD = (VPC, MDS)
  XHJ = (MNP, FTX)
  XVJ = (RGG, BCB)
  DRH = (CDK, JFK)
  BMC = (TTQ, KHR)
  TCT = (JQD, QBB)
  BCS = (HLV, MKR)
  LFV = (GTL, NSX)
  JCS = (JQC, NDG)
  SBJ = (PHS, QMN)
  HPZ = (DQD, PFP)
  BFM = (PMD, JGB)
  QBL = (KVC, TXK)
  RGD = (NXH, KQQ)
  PBX = (LBP, FPK)
  FDD = (TCX, CSN)
  RJT = (CQG, JSQ)
  BMR = (FPK, LBP)
  RBN = (DRF, VJB)
  PHB = (NXR, LPM)
  BPN = (PPX, PPX)
  KVC = (NSF, TQK)
  PXB = (GJH, JHM)
  BCB = (NTR, KKB)
  KXM = (NHS, HHQ)
  VTT = (NCB, HCR)
  SHP = (LQX, XJH)
  RCG = (CLL, TCT)
  LHG = (GSF, PRJ)
  XCL = (JLX, PRV)
  LXB = (RHH, RXS)
  FKZ = (TJS, BJB)
  NNH = (CFD, XMX)
  NTD = (NCX, PVK)
  DCF = (JHJ, VMN)
  GJH = (JTD, CJD)
  VBS = (CDQ, LFQ)
  MGL = (GGB, QNN)
  TXK = (NSF, TQK)
  HRX = (QFP, BJR)
  GMS = (GKJ, TNF)
  RGA = (PFP, DQD)
  KTS = (GSF, PRJ)
  TPP = (VPC, MDS)
  JNV = (BHV, XQK)
  DXL = (HDP, KTG)
  MBR = (GRS, GTG)
  KVJ = (LPH, NGG)
  HRG = (RNL, MJQ)
  XHL = (JXF, FVH)
  MMC = (FHM, HNF)
  HGC = (SHT, HBF)
  LPS = (NTV, CGR)
  FKR = (CBR, VDR)
  BHV = (PQG, QTK)
  BKF = (SRP, DRH)
  JMA = (BJB, TJS)
  MPT = (HRX, VSD)
  QHL = (NRB, HJG)
  PDG = (KJM, SHP)
  HFT = (HHQ, NHS)
  SJD = (GPM, PPB)
  NSF = (NRX, SRL)
  MXG = (JVJ, BMF)
  PHD = (BQK, VKV)
  VBH = (TXK, KVC)
  NJM = (HTD, MGK)
  TVV = (LLH, HFB)
  RPS = (GGQ, SNK)
  HPR = (LJS, DJR)
  FDR = (QKT, GRX)
  LLT = (SHV, NRL)
  VQC = (DPM, DMQ)
  MJQ = (CLD, FCV)
  BFG = (GJH, JHM)
  GFS = (PMP, VXL)
  LBP = (HRF, GRB)
  BXC = (MFS, NRM)
  CFD = (QMQ, HPR)
  HPN = (JQC, NDG)
  BBJ = (JTL, QQK)
  VVL = (CDN, STB)
  HFB = (CFP, BGF)
  NNG = (XVP, CQH)
  QKM = (KDS, FRP)
  VJB = (CPR, RTX)
  KQB = (XCK, BSF)
  LKS = (LDJ, MXG)
  GTL = (FVD, LXB)
  PJS = (BGV, MLM)
  KNM = (FCN, VMH)
  FCN = (VGR, KHV)
  RPJ = (XKD, BPM)
  GLP = (KDR, RTV)
  NXL = (VTS, SDL)
  XDX = (MPT, FXH)
  KRX = (DCD, DHH)
  CTP = (CRQ, DPL)
  SRG = (SKH, SLF)
  QVX = (NDC, NPL)
  XVK = (SNB, JQF)
  RBT = (NSD, SBJ)
  RXS = (FKC, JSS)
  SFX = (PRB, MLT)
  SRS = (FVH, JXF)
  NRL = (RLG, HRG)
  QKK = (PBX, BMR)
  DPL = (PTQ, DBH)
  PFD = (JQV, GKK)
  VGR = (KMX, DVR)
  FQX = (LHD, PTF)
  LXT = (RHM, FQX)
  JHV = (MBR, PHJ)
  JNN = (VKG, SLT)
  XDK = (DRH, SRP)
  JBR = (BDR, GFS)
  BNM = (VKG, SLT)
  CJD = (VNS, FGJ)
  FPK = (HRF, GRB)
  PBH = (JNH, RCS)
  FGV = (FDR, TMD)
  LSF = (XXP, QDR)
  RBM = (VHG, BDL)
  TNF = (HQJ, TQF)
  TRM = (JHT, BCG)
  GBH = (XMJ, JFF)
  DBH = (DSS, RQL)
  PGB = (BXR, DXL)
  QFR = (TDT, TCC)
  HHL = (NXH, KQQ)
  HGN = (BFG, PXB)
  PXC = (BPN, BPN)
  NDF = (VQC, NQX)
  GSK = (BVV, SBX)
  TCM = (VBS, HCN)
  HTD = (BVC, HVL)
  SHD = (MHG, HNG)
  LQX = (QVF, LBV)
  MSF = (FDF, VLP)
  NRP = (VMN, JHJ)
  TQF = (BXC, JCR)
  MBX = (GML, FDD)
  JCR = (MFS, NRM)
  NTR = (PCN, RNT)
  JHJ = (XMT, NPT)
  SQX = (CDN, STB)
  CSN = (GBJ, PGB)
  GDJ = (GBM, GCJ)
  XGL = (HJQ, FNV)
  PLD = (BFL, BFL)
  NRX = (LFV, LSP)
  TFF = (HGQ, MJT)
  JVJ = (TMS, HPK)
  BSF = (VDX, GFC)
  GML = (CSN, TCX)
  BFJ = (GFD, QRR)
  FGJ = (PGF, VMS)
  TQK = (SRL, NRX)
  GQD = (MDD, HLQ)
  TJX = (XCG, DJH)
  GRR = (LPM, NXR)
  PTQ = (DSS, DSS)
  HHK = (KLD, NNG)
  FBR = (KXM, HFT)
  RLT = (JMK, DLP)
  PHL = (QHR, RMH)
  DVM = (JTP, KDM)
  MNF = (RPJ, RMF)
  RMF = (BPM, XKD)
  GGQ = (MFT, BTG)
  CLD = (NLP, QJK)
  NMR = (FNL, LXT)
  CLX = (TRP, GMD)
  QMQ = (DJR, LJS)
  KDR = (PKC, NRF)
  KKG = (VHG, BDL)
  FBQ = (TPP, HHD)
  QVV = (LNR, GSK)
  VKV = (MFX, FDL)
  HJG = (NQD, RFT)
  XVD = (VXT, BPR)
  NCX = (SMV, JRN)
  QLN = (CDJ, TDK)
  GFC = (CKR, LNC)
  HGQ = (JNR, PGC)
  NDG = (RJF, HNQ)
  CBC = (NSD, SBJ)
  BQK = (FDL, MFX)
  VGV = (HGC, TQG)
  VGP = (RJT, KPK)
  VMN = (XMT, NPT)
  PSH = (NSS, RGK)
  PPL = (FXH, MPT)
  DCD = (SBR, DTS)
  MDD = (MQX, FQT)
  XCG = (XVK, TTV)
  LFQ = (SNS, VBL)
  JHT = (FMN, HMC)
  KNQ = (QKM, DPS)
  PVM = (CHL, GLT)
  JMG = (KPK, RJT)
  XKD = (GQJ, NXL)
  DGG = (CCB, CQX)
  HNF = (MNC, FKZ)
  QTL = (PSH, JBH)
  RNL = (CLD, FCV)
  BDR = (PMP, VXL)
  GKH = (KXM, HFT)
  RQC = (DVM, BJM)
  GSR = (PPL, XDX)
  JQD = (GNH, XSC)
  GRS = (RTN, MPH)
  BPP = (GBH, KQX)
  XVP = (HJL, FKR)
  PKZ = (NMR, KJK)
  SLT = (BVM, KMJ)
  XHA = (KJK, NMR)
  BQQ = (FDR, TMD)
  GGC = (CXJ, PTJ)
  NBM = (PXB, BFG)
  RQL = (BBH, NLT)
  KJK = (FNL, LXT)
  PSK = (GGB, QNN)
  FQT = (DRL, NDS)
  SJT = (VQC, NQX)
  QHT = (GFS, BDR)
  QJT = (PJS, DNG)
  SVT = (PDG, GSS)
  MBQ = (PPL, XDX)
  VHL = (PVM, JBG)
  QCJ = (JKK, JSR)
  NQH = (LKQ, FBG)
  XNJ = (QNF, LPL)
  PQV = (CKJ, JHV)
  FHM = (MNC, MNC)
  FPN = (DLQ, BGR)
  BJR = (NJM, FSB)
  HPQ = (PRV, JLX)
  KMJ = (QLL, RCG)
  FTX = (TSM, PDR)
  JXT = (KLD, NNG)
  DPS = (KDS, FRP)
  KKB = (RNT, PCN)
  XCB = (TDM, HXC)
  TCP = (PFP, DQD)
  CDK = (NDF, SJT)
  HCR = (HSP, PFD)
  SNK = (BTG, MFT)
  TKN = (QTL, HPL)
  GSS = (KJM, SHP)
  NRF = (SVT, RGV)
  FLV = (GKJ, TNF)
  QPK = (FPN, DRM)
  RNB = (QTL, HPL)
  HPJ = (XGL, JVX)
  NSD = (QMN, PHS)
  JXF = (DQV, XPX)
  PRJ = (KBH, NQM)
  XMT = (NGC, FQM)
  JLP = (QNF, LPL)
  RND = (HLV, MKR)
  QRR = (GPQ, GLL)
  LNR = (BVV, SBX)
  PQG = (TXR, NTD)
  JXX = (PJS, DNG)
  QQX = (VTT, XKV)
  RRJ = (GLS, GGP)
  MLM = (VCD, BTQ)
  QVG = (TMM, CTP)
  KRM = (MSF, HVT)
  XKV = (HCR, NCB)
  LJX = (RNB, TKN)
  CCB = (NXM, QSG)
  RJF = (FQP, VDH)
  XBN = (BJQ, CHJ)
  JHM = (JTD, CJD)
  SMV = (RSL, RLD)
  PDR = (GHX, XBN)
  JFK = (NDF, SJT)
  HCN = (LFQ, CDQ)
  SLL = (TCB, GDK)
  VBL = (JBR, QHT)
  SMK = (RBM, KKG)
  GDK = (QXQ, RVR)
  KQX = (XMJ, JFF)
  LKQ = (HLN, VTD)
  JSQ = (QXG, CLX)
  FFD = (FRX, SSS)
  NRM = (XBP, NQH)
  SBR = (PQQ, SRG)
  BKR = (MHG, HNG)
  QQK = (GQK, STS)
  HVL = (DLF, QLH)
  NHT = (PTJ, CXJ)
  GLL = (TLL, LRR)
  GLS = (PBH, XNG)
  NHB = (QQK, JTL)
  PFS = (KFG, TSS)
  PCN = (PFS, QFB)
  CJV = (BFL, PKZ)
  JFM = (FKG, CXG)
  GFD = (GLL, GPQ)
  MDS = (XCL, HPQ)
  FXH = (VSD, HRX)
  DQD = (RPR, LPS)
  HPX = (RRJ, FCK)
  JNR = (SQQ, SQQ)
  BGR = (PQV, DKS)
  BRN = (BSF, XCK)
  RVS = (QKM, DPS)
  PLH = (GPM, PPB)
  XSM = (QFS, GQD)
  TTH = (TQG, HGC)
  KBJ = (KTS, LHG)
  RKN = (PCX, NSB)
  TPK = (PFM, RFN)
  MNC = (BJB, TJS)
  PMM = (GRR, PHB)
  QKT = (BNK, QKR)
  HQG = (JLP, XNJ)
  RRD = (JGB, PMD)
  CPR = (TGM, VXS)
  GGM = (GCJ, GBM)
  HBF = (FQG, PHL)
  NXH = (DPF, GKD)
  TMD = (GRX, QKT)
  FBL = (RQC, TMK)
  GNB = (DKH, TNC)
  LQF = (LKS, KPG)
  BKN = (TRN, TRN)
  QJK = (BLT, XVJ)
  HLV = (TJX, XPQ)
  XPX = (TPK, HQN)
  BJP = (FJB, FRM)
  GHD = (KNM, BJG)
  XMX = (HPR, QMQ)
  FNV = (NHT, GGC)
  JGB = (HGN, NBM)
  PKH = (HHK, JXT)
  JXN = (VRR, VRR)
  CHJ = (TLF, QSN)
  XBP = (LKQ, FBG)
  QTK = (TXR, NTD)
  PKC = (SVT, RGV)
  JNH = (MGV, MPJ)
  FXB = (NDC, NPL)
  XHQ = (KTS, LHG)
  MFS = (NQH, XBP)
  FQM = (XJB, TXN)
  QNN = (JQQ, GBG)
  GBG = (PKD, GNB)
  TMN = (GRC, BCV)
  HMN = (KKG, RBM)
  DHH = (SBR, DTS)
  KPG = (LDJ, MXG)
  FDL = (LQF, FSM)
  FXX = (LLH, HFB)
  VSD = (BJR, QFP)
  HVT = (FDF, VLP)
  FRM = (CBB, GMX)
  GQK = (QVV, QBV)
  CKJ = (PHJ, MBR)
  JJH = (XSH, BMC)
  SQQ = (PLD, PLD)
  KPK = (JSQ, CQG)
  VLP = (HHT, MMC)
  NLP = (XVJ, BLT)
  VTS = (MGL, PSK)
  DTS = (SRG, PQQ)
  VCD = (GDJ, GGM)
  VRR = (HLR, RKL)
  VXS = (BKN, SRB)
  GMD = (PSR, VRX)
  PFK = (HXC, TDM)
  SJP = (VSM, NNH)
  TDK = (SRS, XHL)
  KRS = (GCV, SJB)
  MRQ = (CJK, PQD)
  XJB = (JRK, RPS)
  BGF = (QCR, LJX)
  MLT = (MMF, DGG)
  TCC = (MNF, KKL)
  QMN = (GLN, SQH)
  GQJ = (VTS, SDL)
  BFQ = (SMK, HMN)
  NSS = (JPQ, HXV)
  MHG = (VGV, TTH)
  KBH = (GPL, XCV)
  DRL = (KGD, HNX)
  HMC = (QDF, RGR)
  QSN = (FBR, GKH)
  SDD = (GRC, BCV)
  TGH = (BPN, SSQ)
  HNG = (TTH, VGV)
  RHH = (FKC, JSS)
  DQA = (MVV, LQJ)
  QFB = (KFG, TSS)
  TQG = (SHT, HBF)
  KDM = (QKK, HQL)
  XHV = (PLD, CJV)
  PQD = (TPH, PTN)
  SSS = (SQX, VVL)
  GPM = (DXB, GDX)
  KLD = (CQH, XVP)
  LRR = (FXX, TVV)
  HPL = (JBH, PSH)
  TMS = (BQQ, FGV)
  MMF = (CCB, CQX)
  DLQ = (PQV, DKS)
  PHJ = (GTG, GRS)
  TLF = (GKH, FBR)
  FJB = (CBB, GMX)
  PTF = (PSF, PHD)
  NPL = (RTG, QHL)
  XMJ = (XHQ, KBJ)
  PMP = (TRM, PJK)
  JPQ = (KLM, TCM)
  BCG = (FMN, HMC)
  DRS = (MGD, XVD)
  RGT = (PKH, XGH)
  TGM = (BKN, BKN)
  BPM = (GQJ, NXL)
  VDX = (CKR, LNC)
  XJH = (QVF, LBV)
  MGD = (BPR, VXT)
  RGR = (JSK, VHL)
  SNS = (QHT, JBR)
  SRB = (TRN, DVK)
  NRQ = (LQC, JJH)
  PSF = (BQK, VKV)
  BMF = (TMS, HPK)
  LGG = (FCK, RRJ)
  HPK = (FGV, BQQ)
  QBV = (GSK, LNR)
  FNF = (PHB, GRR)
  GLT = (JDP, GNC)
  DKS = (JHV, CKJ)
  RGV = (GSS, PDG)
  HQN = (PFM, RFN)
  GKD = (BFJ, JKF)
  HXC = (HPN, JCS)
  MGH = (BVB, FBQ)
  LBV = (XCB, PFK)
  LHD = (PHD, PSF)
  CDQ = (SNS, VBL)
  BTQ = (GGM, GDJ)
  HMS = (CBC, RBT)
  VTD = (CNV, NRQ)
  JBG = (GLT, CHL)
  LCB = (NGG, LPH)
  FKG = (SDD, TMN)
  BVV = (DDL, MGH)
  RGG = (KKB, NTR)
  FBG = (HLN, VTD)
  KMX = (GVJ, LLT)
  HRF = (HHL, RGD)
  DGM = (QFS, GQD)
  LPM = (QFR, GCG)
  QXQ = (BCS, RND)
  BGV = (BTQ, VCD)
  BGX = (XKV, VTT)
  XDR = (VRR, ZZZ)
  BJM = (JTP, KDM)
  RFN = (PGQ, XHJ)
  DDL = (FBQ, BVB)
  XCV = (JNN, BNM)
  TCX = (GBJ, PGB)
  QXG = (TRP, GMD)
  VKG = (BVM, KMJ)
  RSL = (RLV, BJP)
  CDN = (QLN, CNM)
  RVR = (BCS, RND)
  BBH = (BXJ, BXJ)
  BXR = (KTG, HDP)
  DJH = (XVK, TTV)
  DVK = (TCP, HPZ)
  SLF = (TFF, KQV)
  DJR = (SFX, KGN)
  HHT = (FHM, FHM)
  JSR = (JXM, JNV)
  DSB = (BFQ, XDD)
  DPM = (RVS, KNQ)
  HJQ = (NHT, GGC)
  ZZZ = (RKL, HLR)
  RJL = (HPJ, PNJ)
  BJQ = (TLF, QSN)
  HQJ = (BXC, JCR)
  FQP = (HMS, SRH)
  PGF = (VLQ, KRX)
  LQJ = (FNF, PMM)
  JXM = (BHV, XQK)
  PNJ = (JVX, XGL)
  STB = (CNM, QLN)
  BBS = (JXN, JXN)
  KKL = (RMF, RPJ)
  SHV = (HRG, RLG)
  FPQ = (FPN, DRM)
  GBJ = (DXL, BXR)
  QHR = (GHD, MPF)
  MDG = (JKK, JSR)
  CRQ = (PTQ, DBH)
  BVB = (TPP, HHD)
  GRC = (RGT, VDD)
  SKH = (TFF, KQV)
  DHZ = (LQJ, MVV)
  LSP = (NSX, GTL)
  MPJ = (QBL, VBH)
  TDT = (KKL, MNF)
  TXN = (JRK, RPS)
  HSP = (GKK, JQV)
  JTL = (STS, GQK)
  GBM = (QCJ, MDG)
  HDP = (LLX, QVG)
  GMX = (KQB, BRN)
  PJK = (JHT, BCG)
  NDC = (RTG, QHL)
  LPL = (GSR, MBQ)
  VLQ = (DCD, DHH)
  QLL = (CLL, TCT)
  RTV = (NRF, PKC)
  DKH = (BBJ, NHB)
  NGC = (XJB, TXN)
  CNM = (CDJ, TDK)
  XXP = (BSP, NHC)
  FNL = (RHM, FQX)
  NBN = (VSM, NNH)
  XSC = (BFM, RRD)
  VXL = (PJK, TRM)
  VSM = (XMX, CFD)
  NQM = (GPL, XCV)
  HLN = (CNV, NRQ)
  GCJ = (QCJ, MDG)
  FDF = (HHT, HHT)
  PQQ = (SKH, SLF)
  KVD = (MSF, HVT)
  QSG = (NVD, RBN)
  RGK = (HXV, JPQ)
  NXR = (GCG, QFR)
  QDR = (BSP, NHC)
  TDM = (HPN, JCS)
  MQX = (NDS, DRL)
  JRK = (GGQ, SNK)
  VMH = (VGR, KHV)
  RPR = (NTV, CGR)
  CFP = (LJX, QCR)
  CLL = (JQD, QBB)
  LLX = (CTP, TMM)
  PRB = (DGG, MMF)
  FVH = (XPX, DQV)
  JKK = (JNV, JXM)
  KLM = (VBS, HCN)
  NHQ = (CJK, PQD)
  BJB = (BKR, SHD)
  CQX = (NXM, QSG)
  KHV = (DVR, KMX)
  SRH = (CBC, RBT)
  DQV = (TPK, HQN)
  NQD = (GMS, FLV)
  PHS = (GLN, SQH)
  GPL = (JNN, BNM)
  JSS = (SJP, NBN)
  CGR = (MRQ, NHQ)
  PGC = (SQQ, XHV)
  GPQ = (LRR, TLL)
  HXV = (TCM, KLM)
  BFL = (KJK, NMR)
  PPX = (FXB, QVX)
  AAA = (HLR, RKL)
  DSS = (BBH, BBH)
  VDD = (PKH, XGH)
  NCB = (PFD, HSP)
  SSQ = (PPX, HJZ)
  DNG = (MLM, BGV)
  CDJ = (XHL, SRS)
  TNC = (NHB, BBJ)
  QDF = (VHL, JSK)
  GTG = (MPH, RTN)
  FRX = (SQX, VVL)
  MVV = (FNF, PMM)
  QFS = (HLQ, MDD)
  MNP = (PDR, TSM)
  LDJ = (BMF, JVJ)
  NSX = (FVD, LXB)
  RNT = (PFS, QFB)
  TJS = (SHD, BKR)
  HNQ = (VDH, FQP)
  BLT = (BCB, RGG)
  KQV = (HGQ, MJT)
  PTN = (NXT, RKN)
  VDR = (BBS, PCT)
  RCS = (MPJ, MGV)
  GRX = (BNK, QKR)
  JFF = (XHQ, KBJ)
  RTG = (NRB, HJG)
  CND = (DCF, NRP)
  DCM = (JMK, DLP)
  XPQ = (XCG, DJH)
  RTX = (TGM, VXS)
  DPF = (BFJ, JKF)
  LNC = (PXC, TGH)
  PCX = (SLL, KSX)
  BSP = (HPX, LGG)
  VHG = (LCH, NHP)
  GRV = (KQX, GBH)
  NGG = (DGM, XSM)
  XSH = (TTQ, KHR)
  MRH = (KVJ, LCB)
  TXR = (NCX, PVK)
  NVD = (VJB, DRF)
  TTQ = (FPQ, QPK)
  CKR = (PXC, PXC)
  BVC = (DLF, QLH)
  VDH = (SRH, HMS)
  JQF = (SKC, MRH)
  CBB = (BRN, KQB)
  FMN = (RGR, QDF)
  SHT = (FQG, PHL)
  NLT = (BXJ, DHZ)
  MPH = (KRS, XNV)
  BXJ = (MVV, LQJ)
  CHL = (JDP, GNC)
  TSM = (XBN, GHX)
  DLF = (KRM, KVD)
  BCV = (RGT, VDD)
  HNX = (FNK, LSF)
  LJS = (SFX, KGN)
  STS = (QBV, QVV)
  SKC = (KVJ, LCB)
  BNK = (SJD, PLH)
  RTN = (KRS, XNV)
  JTP = (QKK, HQL)
  LCH = (VGP, JMG)
  CBR = (BBS, BBS)
  VNS = (VMS, PGF)
  CQG = (CLX, QXG)
  HLQ = (MQX, FQT)
  TMM = (CRQ, DPL)
  BDL = (NHP, LCH)
  TRP = (VRX, PSR)
  MGV = (VBH, QBL)
  GNH = (BFM, RRD)
  NXT = (NSB, PCX)
  SNB = (SKC, MRH)
  LPH = (XSM, DGM)
  GGB = (GBG, JQQ)
  CJK = (PTN, TPH)
  QVF = (PFK, XCB)")
;; day8-input-scm ends here

;; Data Definition and Extraction

;; #+NAME: day8-part1-records

;; [[file:chicken-src.org::day8-part1-records][day8-part1-records]]
;; -*- geiser-scheme-implementation: chicken -*-
(define-record node name left right)
(define-record direction side)
(define-record directions-ring entries entry length index)
;; day8-part1-records ends here



;; #+NAME: day8-part1-irregex

;; [[file:chicken-src.org::day8-part1-irregex][day8-part1-irregex]]
;; -*- geiser-scheme-implementation: chicken -*-
(define alnum '(+ (or (/ #\A #\Z)
                      (/ #\0 #\9))))

(define node-irregex
  `(: bol
      (* whitespace)
      (submatch-named node-name ,alnum)
      " = ("
      (submatch-named left ,alnum)
      ", "
      (submatch-named right ,alnum)
      ")"
      (* whitespace)
      eol))

(define directions-irregex
  '(+ (or #\L #\R)))
;; day8-part1-irregex ends here



;; #+NAME: day8-part1-input--directions

;; [[file:chicken-src.org::day8-part1-input--directions][day8-part1-input--directions]]
;; -*- geiser-scheme-implementation: chicken -*-
(define (input->directions input)
  (let* ((directions-str (car (irregex-extract directions-irregex input)))
         (directions (map (compose make-direction string->symbol string) (string->list directions-str))))
    (make-directions-ring directions
                          (car directions)
                          (length directions)
                          0)))
;; day8-part1-input--directions ends here



;; #+NAME: day8-part1-input--nodes-alist

;; [[file:chicken-src.org::day8-part1-input--nodes-alist][day8-part1-input--nodes-alist]]
;; -*- geiser-scheme-implementation: chicken -*-
(define (input->nodes-alist input)
  (irregex-fold node-irregex
                (lambda (from-index match seed)
                  (alist-update
                   (string->symbol (irregex-match-substring match 'node-name))
                   (make-node (string->symbol (irregex-match-substring match 'node-name))
                              (string->symbol (irregex-match-substring match 'left))
                              (string->symbol (irregex-match-substring match 'right)))
                   seed))
                '() input))
;; day8-part1-input--nodes-alist ends here

;; Navigation

;; #+NAME: day8-part1-move-forward

;; [[file:chicken-src.org::day8-part1-move-forward][day8-part1-move-forward]]
;; -*- geiser-scheme-implementation: chicken -*-
(define (move-forward directions-ring)
  (let ((entries (directions-ring-entries directions-ring))
        (len     (directions-ring-length directions-ring))
        (index   (directions-ring-index directions-ring)))
    (directions-ring-index-set! directions-ring
                                (or (and (< index (- len 1))
                                         (+ index 1))
                                    0))
    (directions-ring-entry-set! directions-ring
                                (list-ref entries (directions-ring-index directions-ring)))
    directions-ring))
;; day8-part1-move-forward ends here



;; #+NAME: day8-part1-move

;; [[file:chicken-src.org::day8-part1-move][day8-part1-move]]
;; -*- geiser-scheme-implementation: chicken -*-
(define (move node direction nodes-alist)
  (let* ((side (direction-side direction))
         (next-sym (if (eqv? 'L side)
                       (node-left node)
                       (node-right node))))
    (alist-ref next-sym nodes-alist)))
;; day8-part1-move ends here



;; #+NAME: day8-part1-navigate

;; [[file:chicken-src.org::day8-part1-navigate][day8-part1-navigate]]
;; -*- geiser-scheme-implementation: chicken -*-
(define (navigate nodes-alist directions start-sym target-sym
                  #!optional (current-sym start-sym) (counter 0))
  (if (eqv? current-sym target-sym)
      counter
      (let ((next-sym (node-name
                       (move (alist-ref current-sym nodes-alist)
                             (directions-ring-entry directions)
                             nodes-alist))))
        (navigate nodes-alist
                  (move-forward directions)
                  start-sym target-sym
                  next-sym
                  (+ counter 1)))))
;; day8-part1-navigate ends here

;; Calculate The Route

;; #+NAME: day8-part1-calc-fn

;; [[file:chicken-src.org::day8-part1-calc-fn][day8-part1-calc-fn]]
;; -*- geiser-scheme-implementation: chicken -*-








(define (calc-part-1)
  (let ((directions (input->directions input))
        (nodes-alist (input->nodes-alist input)))
    (navigate nodes-alist directions 'AAA 'ZZZ)))
;; day8-part1-calc-fn ends here

;; Puzzle Solution

;; #+NAME: day8-part2-calc-next-sym

;; [[file:chicken-src.org::day8-part2-calc-next-sym][day8-part2-calc-next-sym]]
;; -*- geiser-scheme-implementation: chicken -*-
(define (calc-next-sym sym direction nodes-alist)
  (let ((side (direction-side direction))
        (node (alist-ref sym nodes-alist)))
    (if (eqv? 'L side)
        (node-left node) (node-right node))))
;; day8-part2-calc-next-sym ends here



;; #+NAME: day8-part2-navigate

;; [[file:chicken-src.org::day8-part2-navigate][day8-part2-navigate]]
;; -*- geiser-scheme-implementation: chicken -*-
(define (p2-navigate nodes-alist directions start-sym
                     #!optional (current-sym start-sym) (counter 0))
  (if (eqv? #\Z
            ((compose car reverse string->list symbol->string) current-sym))
      (begin
        (print "Found end point of " start-sym ": " current-sym ", steps: " counter)
        counter)
      (let ((next-sym (calc-next-sym current-sym (directions-ring-entry directions) nodes-alist)))
        (p2-navigate nodes-alist
                     (move-forward directions)
                     start-sym next-sym
                     (+ counter 1)))))
;; day8-part2-navigate ends here



;; #+NAME: day8-part2-find-start-points

;; [[file:chicken-src.org::day8-part2-find-start-points][day8-part2-find-start-points]]
;; -*- geiser-scheme-implementation: chicken -*-
(define (find-start-points sym-list)
  (foldl (lambda (start-points sym)
           (if (eqv? #\A ((compose car reverse string->list symbol->string) sym))
               (cons sym start-points) start-points))
         '() sym-list))
;; day8-part2-find-start-points ends here



;; #+NAME: day8-part2-lcm

;; [[file:chicken-src.org::day8-part2-lcm][day8-part2-lcm]]
;; -*- geiser-scheme-implementation: chicken -*-
(: p2-lcm ((list-of integer) integer -> integer))
(define (p2-lcm numbers #!optional (factor 2))
  (let ((multiple (* (car numbers) factor)))
    (if (= 0 (foldl (lambda (x n) (+ x (modulo multiple n))) 0 numbers))
        multiple
        (p2-lcm numbers (+ factor 1)))))
;; day8-part2-lcm ends here



;; #+NAME: day8-part2-calc-fn

;; [[file:chicken-src.org::day8-part2-calc-fn][day8-part2-calc-fn]]
;; -*- geiser-scheme-implementation: chicken -*-
          
(define (calc-part-2)
  (let* ((directions (input->directions input))
         (nodes-alist (input->nodes-alist input))
         (start-points (find-start-points (map car nodes-alist))))
    (apply lcm
     (sort (map (cut p2-navigate nodes-alist directions <>) start-points) >))))
;; day8-part2-calc-fn ends here