题目描述

Alex doesn't like boredom. That's why whenever he gets bored, he comes up with games. One long winter evening he came up with a game and decided to play it.

Given a sequence a consisting of n integers. The player can make several steps. In a single step he can choose an element of the sequence (let's denote it ak) and delete it, at that all elements equal to ak + 1 and ak - 1 also must be deleted from the sequence. That step brings ak points to the player.

Alex is a perfectionist, so he decided to get as many points as possible. Help him.

输入格式

The first line contains integer n (1 ≤ n ≤ 1e5) that shows how many numbers are in Alex's sequence. The second line contains n integers a1, a2, ..., an (1 ≤ ai ≤ 1e5).

输出格式

Print a single integer — the maximum number of points that Alex can earn.

样例

2 
1 2 

2

3 
1 2 3 

4 

9 
1 2 1 3 2 2 2 2 3 

10

提示

This question comes from a very classic question on the Internet. It is a very good question

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