/*
 * http://acm.hdu.edu.cn/showproblem.php?pid=1250
 * by jtahstu on 2015/3/31 14:00
 */
package 大数;

import java.math.BigInteger;
import java.util.Scanner;

public class HDU1250 {
	public static Scanner cin=new Scanner(System.in);
	public static void main(String[] args) {
		// TODO 自动生成的方法存根
		BigInteger a[]=new BigInteger[1000];
		a[1]=a[2]=a[3]=a[4]=BigInteger.valueOf(1);
		for (int i = 5; i <=999; i++) {
			a[i]=a[i-1].add(a[i-2]).add(a[i-3]).add(a[i-4]);
		}
		while (cin.hasNext()) {
			int n=cin.nextInt();
			
			System.out.println(a[n]);
		}
	}

}