№23 — #23127

from functools import lru_cache
@lru_cache(None)
def f(a, b):
    if a == b:
        return 1
    if a < b:
        return 0
    return f(a - 5, b) + f(a - 7, b) + f(a // 4, b)
@lru_cache(None)
def f1(a, b):
    if a == 8:
        return 0
    if a == b:
        return 1
    if a < b:
        return 0
    return f1(a - 5, b) + f1(a - 7, b) + f1(a // 4, b)
@lru_cache(None)
def f2(a, b):
    if a == 21:
        return 0
    if a == b:
        return 1
    if a < b:
        return 0
    return f2(a - 5, b) + f2(a - 7, b) + f2(a // 4, b)
print(f(84, 21) * f1(21, 3) + f2(84, 8) * f(8, 3))