from functools import reduce


def yield_numbers(line: str, target: int):
    nums = [None]*target
    turn = 0
    last_spoken = 0
    for starting in map(int, line.split(",")):
        nums[last_spoken] = turn
        turn += 1
        last_spoken = starting
        yield turn, last_spoken, nums
    for t in range(turn, target):
        n = t - nums[last_spoken] if nums[last_spoken] is not None else 0
        nums[last_spoken] = t
        last_spoken = n
        yield t+1, last_spoken, nums


def get_target(line: str, target: int):
    return reduce(lambda a, b: b, yield_numbers(line, target))