#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
int func(int x)
{
if(x==1) return 1;
if(x==2) return 2;
if(x==3) return 3;
if(x==4) return 4;
return func(x-1)+func(x-3);
}
int main()
{
int n;
while(scanf("%d",&n)!=EOF)
{
if(!n) break;
printf("%d\n",func(n));
}
return 0;
}