杭电ACM 1001题

 

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        while (sc.hasNext()){
          int sum=0;
          int b=sc.nextInt();
          for(int i=1;i<=b;i++){
              sum=sum+i;
            }
          System.out.println(sum);
          System.out.println("");
        }
    }
}