#!/usr/bin/env python

import copy
from collections import defaultdict

graph = dict()

def calculate_paths(graph, current, small_seen, path):
	if current == 'end':
		return 1
	found = 0
	for n in sorted(graph.get(current)):
		if n == 'start':
			continue
		# already seen, check if there is any with count
		if small_seen[n] > 0:
			tmp = max(small_seen.values())
			if tmp > 1:
				continue
		p = copy.copy(path)
		p.append(n)
		#print("%s -> %s" % (current, n))
		sm = copy.copy(small_seen)
		if n.lower() == n:
			sm[n] += 1
		found += calculate_paths(graph, n, sm, p)
	return found

with open("input01.txt","r") as f:
	for line in f:
		(x,y) = line.strip().split("-",2)
		if x not in graph:
			graph[x] = []
		graph[x].append(y)
		if y not in graph:
			graph[y] = []
		graph[y].append(x)

#print(graph)
small_seen = defaultdict(int)
print(calculate_paths(graph, 'start', small_seen, ['start']))