100430: [AtCoder]ABC043 A - Children and Candies (ABC Edit)

Memory Limit:256 MB Time Limit:2 S
Judge Style:Text Compare Creator:
Submit:2 Solved:0

Description

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.

Input

题意翻译

幼儿园有N个孩子。教授决定给孩子们糖果,第一个人要一个糖果,第二个人要两个糖果…… ,第N个人要N个糖果。总共需要多少糖果?

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