from math import sqrt,ceil,gcd,log;re=lambda:map(int,input().strip().split())
from functools import cache

@cache
def cnt(x):
    if x <= 4:
        return x
    return cnt(x - 1) + cnt(x - 3)

while True:
    n, = re()
    if n == 0:
        break
    print(cnt(n))