23 задание

def F(x, y):
    if x == y:
        return 1;
    elif x == 21:
        return 0
    elif x > y:
        return 0

    return F(x + 1, y) + F(x * 3, y) + F(x * 4, y)


print(F(2, 16) * F(16, 60))