""" Count number of paths through caves """
import pprint
from collections import defaultdict

def walk_from_node(current_node, path_taken_so_far, visited_small_cave_twice=False):
    possible_paths = []
    for node in caves[current_node]:
        if node == "start":
            pass
        elif node == "end":
            possible_paths.append(path_taken_so_far + ["end"])
        elif node == node.lower() and node in path_taken_so_far:
            if not visited_small_cave_twice:
                possible_paths += walk_from_node(node, path_taken_so_far + [current_node], True)
        else:
            possible_paths += walk_from_node(node, path_taken_so_far + [current_node], visited_small_cave_twice)

    return possible_paths

caves = defaultdict(set)

with open("12_input.txt") as f:
    for line in f:
        node_a, node_b = line.strip().split("-")

        caves[node_a].add(node_b)
        caves[node_b].add(node_a)

walked_paths = walk_from_node("start", [])
print(len(walked_paths))