F. [GESP202306 一级] 累计相加

Type: RemoteJudge

1000ms

128MiB

You cannot submit for this problem because the contest is ended. You can click "Open in Problem Set" to view this problem in normal mode.

题目描述

输入一个正整数 $n$ ，求形如：

$1+(1+2)+(1+2+3)+(1+2+3+4)+ \cdots +(1+2+3+4+5+ \cdots +n)$ 的累计相加。

输入一个正整数 $n$ 。约定 $1<n \le 100$ 。

输出累计相加的结果。