HDOJ 1001 java

import java.util.Scanner;


public class Main {

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

}