#!/usr/bin/env python

import copy
graph = dict()

def calculate_paths(graph, current, small_seen, path):
	found = 0
	for n in graph.get(current):
		if n == 'start':
			continue
		if n in small_seen:
			continue
		p = copy.copy(path)
		p.append(n)
		#print(p)
		#print("%s -> %s" % (current, n))
		if n == 'end':
			found += 1
			continue
		sm = copy.copy(small_seen)
		if n.lower() == n:
			sm.append(n)
		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)
print(calculate_paths(graph, 'start', [], ['start']))