# Bear and Bowling

## 题意翻译

- 给定一个长度为 $n$ 的序列 $a_{1\dots n}$。 - 你要求一个 $a$ 的子序列 $b_{1\dots m}$（可以为空），使得 $\sum_{i=1}^m ib_i$ 的值最大。 - $n \le 10^5$，$|a_i| \le 10^7$。

## 题目描述

Limak is an old brown bear. He often goes bowling with his friends. Today he feels really good and tries to beat his own record! For rolling a ball one gets a score — an integer (maybe negative) number of points. Score for $i$ -th roll is multiplied by $i$ and scores are summed up. So, for $k$ rolls with scores $s_{1},s_{2},...,s_{k}$ , total score is ![](https://cdn.luogu.com.cn/upload/vjudge_pic/CF573E/dc22606298d977fae92bc67b7a4815c447193831.png). Total score is $0$ if there were no rolls. Limak made $n$ rolls and got score $a_{i}$ for $i$ -th of them. He wants to maximize his total score and he came up with an interesting idea. He will cancel some rolls, saying that something distracted him or there was a strong wind. Limak is able to cancel any number of rolls, maybe even all or none of them. Total score is calculated as if there were only non-canceled rolls. Look at the sample tests for clarification. What maximum total score can Limak get?

## 输入输出格式

### 输入格式

The first line contains single integer $n$ ( $1<=n<=10^{5}$ ). The second line contains $n$ space-separated integers $a_{1},a_{2},...,a_{n}$ ( $|a_{i}|<=10^{7})$ - scores for Limak's rolls.

### 输出格式

Print the maximum possible total score after choosing rolls to cancel.

## 输入输出样例

### 输入样例 #1

5
-2 -8 0 5 -3


### 输出样例 #1

13


### 输入样例 #2

6
-10 20 -30 40 -50 60


### 输出样例 #2

400


## 说明

In first sample Limak should cancel rolls with scores $-8$ and $-3$ . Then he is left with three rolls with scores $-2,0,5$ . Total score is $1·(-2)+2·0+3·5=13$ . In second sample Limak should cancel roll with score $-50$ . Total score is $1·(-10)+2·20+3·(-30)+4·40+5·60=400$ .