Problem:
Score : 100 points

Problem Statement

There are N children in AtCoder Kindergarten. Mr. Evi will arrange the children in a line, then give 1 candy to the first child in the line, 2 candies to the second child, ..., N candies to the N-th child. How many candies will be necessary in total?

Constraints

1≦N≦100

Input

The input is given from Standard Input in the following format:

N

Output

Print the necessary number of candies in total.

Sample Input 1

3

Sample Output 1

6

The answer is 1+2+3=6.

Sample Input 2

10

Sample Output 2

55

The sum of the integers from 1 to 10 is 55.

Sample Input 3

1

Sample Output 3

1

Only one child. The answer is 1 in this case.

Solution in Java7 (OpenJDK 1.7.0) (judge verdict: Accepted)

import java.util.Scanner;


class Main{
    public static void main(String args[]){
	//	print();
	int x ;
	Scanner scan = new Scanner(System.in);

	x = scan.nextInt();

	if(x>100){
	    return;
	}

	int sum = 0;
	for(int n=1;1 <= n &&n <= x;n++){
	    sum = sum + n;
	}
	System.out.println(sum);

    }
    static void print(){
	System.out.println("hello world");
	return;
    }
}//1からnまで足す