#! /usr/local/bin/python3

def tarai(x, y, z, cache={}):
    if x <= y:
        return y
    key = (x, y, z)
    val = cache.get(key)
    if val is not None:
        return val
    val = tarai(
        tarai(x-1, y, z, cache),
        tarai(y-1, z, x, cache),
        tarai(z-1, x, y, cache),
        cache
    )
    cache[key] = val
    return val

print(tarai(100, 50, 0))