#include <algorithm>
#include <iostream>
using namespace std;
int A[128], N;
int main(){
	while (cin >> N && N!=0){
		A[0] = 1;
		for (int i=1; i<=N; i++){
			A[i] = A[i-1];
			if (i>1) A[i] += A[i-2];
			if (i>2) A[i] += A[i-3];
		}
		cout << A[N] << endl;
	}
}