hdu2018

#include<cstdio>
#include<iostream>
#include<cstring>
using namespace std;
const int maxn = 110;
int n, dp[maxn];
int main(void){
    dp[1] = 1;
    dp[2] = 2;
    dp[3] = 3;
    for(int i = 4; i <= 60; ++i)
        dp[i] = dp[i - 1] + dp[i - 3];
    while(scanf("%d", &n) && n){
        printf("%d\n", dp[n]);
    }
}