def f(curr, end):
    if curr < end:
        return 0
    if curr == end:
        return 1
    if curr > end:
        return f(curr - 2, end) + f(curr - 5, end)
print(f(23, 2))

a = [0] * 100
a[23] = 1
for i in range(23, 2, -1):
    if i - 2 >= 2:
        a[i - 2] += a[i]
    if i - 5 >= 2:
        a[i - 5] += a[i]
print(a[2])