def f(curr, end):
    if curr < end:
        return 0
    if curr == end:
        return 1
    if curr > end:
        return f(curr - 1, end) + f(curr - 3, end) + f(curr // 3, end)
print(f(22, 2))

a = [0] * 100
a[22] = 1
for i in range(22, 2, -1):
    if i - 1 >= 2:
        a[i - 1] += a[i]
    if i - 3 >= 2:
        a[i - 3] += a[i]
    if i // 3 >= 2:
        a[i // 3] += a[i]
print(a[2])