Sum Problem

题目:

Problem Description

Hey, welcome to HDOJ(Hangzhou Dianzi University Online Judge).

In this problem, your task is to calculate SUM(n) = 1 + 2 + 3 + ... + n.

Input

The input will consist of a series of integers n, one integer per line.

Output

For each case, output SUM(n) in one line, followed by a blank line. You may assume the result will be in the range of 32-bit signed integer.

Sample Input

1
100

Sample Output

1

5050

<code>

#include<stdio.h>
void main()
{ int n,sum;
  while(scanf("%d",&n)!=EOF)
  { for(sum=0;n>0;n--)
     sum=sum+n;
   printf("%d",sum);
  putchar('\n');
  putchar('\n');}
}