CF573E.Bear and Bowling

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 . 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?

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.

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

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 $1·(-10)+2·20+3·(-30)+4·40+5·60=400$ .