1349 : Sum Problem

时间限制:1 Sec 内存限制:128 MiB
提交:202 答案正确:90

提交 状态 讨论区

题目描述

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

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

输入

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

输出

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.

样例输入

复制
1
100

样例输出

复制
1

5050

提示


			

来源

DOOM III