#B. 序列求和

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Type: Default

1000ms

256MiB

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Description

求1+2+3+...+n的值。

Format

Input

输入包括一个整数n。

Output

输出一行，包括一个整数，表示1+2+3+...+n的值。(1 <=n <= 100000000)

Samples

Limitation

1s, 1024KiB for each test case.

第七届SWPU-ACM新生预选赛

Status: Done
Rule: ACM/ICPC
Problem: 103
Start at: 2022-9-19 14:00
End at: 2022-10-28 14:00
Duration: 936 hour(s)
Host: oyf
Partic.: 58