/**
 * Created by iyasuwatts on 10/17/17.
 */
import java.util.Scanner;

public class Main {

    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        System.out.println("Enter a number: ");
        int input = scan.nextInt();
        int result = 0;

        for (int i = 0; i <= input; i++) {
            result += i;
        }

        System.out.println("Your answer is: " + result);
    }

}