#!/usr/bin/env python3

import sys
import re
from copy import deepcopy

def parse(l):
    groups = re.compile(r"(?P<p1>\w+)-(?P<p2>\w+)").search(l)
    p1, p2 = groups.groups()
    for p in (p1,p2):
        if not p in opts.keys(): opts[p] = set()
        if not p in opts.keys(): opts[p] = set()
        if p.islower() and p not in ('start', 'end'): opts['small'].add(p)
        if p.islower() and p not in ('start', 'end'): opts['small'].add(p)
    opts[p1].add(p2)
    opts[p2].add(p1)    

def paths(p1, l, twice=''):
    p = deepcopy(p1)
    p.append(l)
    if p.count(twice) > 1: twice = ''
    if l == 'end':
        pths.add(tuple(p))
        return
    for n in opts[l]:
        if not ((n != twice and n in p and n in opts['small']) or n == 'start'):
            paths(p, n, twice)

if __name__ == '__main__':
    lines = open(sys.argv[1]).read().strip('\n\n').split('\n') # or split \n\n or sth similar
    
    opts = {'start': set(), 'end': set(), 'small': set()}
    [parse(i) for i in lines]

    # challenge 1
    pths = set()
    paths([], 'start')

    res1 = str(len(pths))
    print("challenge 1:" +"\n" +  res1 + "\n")

    # challenge 2
    pths = set()
    [paths([], 'start', t) for t in opts['small']]

    res2 = str(len(pths))
    print("challenge 2:" +"\n" +  res2 + "\n")