kms152000 2024. 4. 11. 01:08

import java.util.Scanner;

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

        Scanner scanner = new Scanner(System.in);

        int n = scanner.nextInt();
        int k = 0;

        for (int i = 1; i <= n; i++) {
            k = k + i;

        }
        System.out.println(k);
    }
}