합

www.acmicpc.net/problem/8393

8393번: 합

 

import java.util.Scanner;

public class plus {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int a = sc.nextInt();
        int sum =0;

        for(int i = 0 ; i <= a; i++){
            sum += i;
        }

        System.out.println(sum);

    }
}