题目描述
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-----
3
-----Sample Output-----
6
The answer is 1+2+3=6.
输入格式
见题面
输出格式
见题面
样例输入
3
样例输出
6