19-21 нисходящая

#рекурсия для задачи с камнями
from icecream import ic
from functools import lru_cache


@lru_cache(None)
def f(x, y):
    # ic(x, y)
    if x + y <= 20:
        # ic('<= 20')
        return 0
        # ic('вернули 0')
    if x == 0:
        # ic()
        # ic('x == 0')
        moves = [f(x, y - 1), f(x, int(y / 2) + y % 2)]
        return 0
    if x == 1:
        # ic()
        # ic('x == 1')
        moves = [f(x - 1, y), f(x, y - 1), f(x, int(y / 2) + y % 2)]
        return 0
    if y == 0:
        # ic()
        # ic('y == 0')
        moves = [f(x - 1, y), f(int(x / 2) + x % 2, y)]
        return 0
    if y == 1:
        # ic()
        # ic('x == 1')
        moves = [f(x - 1, y), f(x, y - 1), f(int(x / 2) + x % 2, y)]
        return 0
    else:
        moves = [f(x - 1, y), f(x, y - 1), f(int(x / 2) + x % 2, y), f(x, int(y / 2) + y % 2)]
    lose = [i for i in moves if i <= 0]
    # ic(moves)
    # ic(lose)
    if lose:
        result = -max(lose) + 1
    else:
        result = -max(moves)
    return result


ic.configureOutput(prefix='')
for s in range(11, 50):
    if f(10, s) == 2:
        ic(s, f(10, s))
        ic('=====================')