View Code of Problem 30

import java.util.Scanner;
public class Main {
	public static void main(String []args){
	
		Scanner s=new Scanner(System.in);
		while(s.hasNext())	{
		int a=s.nextInt();
		int sum=0;
				for(int i=1;i<=a;i++){
					sum+=i;
				}
				System.out.println(sum);
		}
	}
}