[백준/Java] 8393 : 합

import java.io.*;

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

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        int a = Integer.parseInt(br.readLine());
        int result =0;
        
        while (a != 0){
            result+=a;
            a--;
        }
        
        bw.write(String.valueOf(result));
        bw.flush();
        bw.close();
    }
}