acm 2018 java

import java.util.Scanner;

/**
 * Created by Administrator on 2016/4/4.
 */

public class Main {
    public static void main(String args[]) {

        Scanner in = new Scanner(System.in);
        for (; ; ) {
            int n = in.nextInt();
            if (n == 0) {
                System.exit(0);
            } else if (n > 0) {
                int a = 0, b = 0, c = 0;
                int d = 1;
                int sum = 0;
                for (int i = 1; i < n; i++) {
                    d = d + c;
                    c = b;
                    b = a;
                    a = d;


                }
                sum = a + b + c + d;
                System.out.println(sum);
            }


        }
    }

}