aoc

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from functools import reduce


data = """COM)B
B)C
C)D
D)E
E)F
B)G
G)H
D)I
E)J
J)K
K)L"""

data = """COM)B
B)C
C)D
D)E
E)F
B)G
G)H
D)I
E)J
J)K
K)L
K)YOU
I)SAN"""


def add(a, b):
    return a + b


def assert_root(lines):
    orbitors = []
    orbitees = []

    for line in lines:
        a, b = line.split(')')
        orbitors.append(b)
        orbitees.append(a)

    orbitors = set(orbitors)
    orbitees = set(orbitees)

    root = orbitees.difference(orbitors)
    assert len(root) == 1
    assert 'COM' in root


def count(x, k, n=0):
    c = 0
    c += n

    for item in x.get(k, []):
        c += count(x, item, n + 1)

    return c


def path(x, k):
    if k == 'COM':
        return []
    return [x[k]] + path(x, x[k])


def main():
    x = {}

    data = open('input').read()

    lines = data.splitlines()

    assert_root(lines)

    for line in lines:
        a, b = line.split(')')
        x[b] = a

    you_path = path(x, 'YOU')
    san_path = path(x, 'SAN')

    you_path.reverse()
    san_path.reverse()

    common = []

    for y, s in zip(you_path, san_path):
        if y == s:
            common.append(y)
        else:
            break

    print(you_path)
    print(san_path)
    print(common)

    res = (len(you_path) - len(common)) + (len(san_path) - len(common))
    print(res)



if __name__ == '__main__':
    main()