Codeforces 455A - Boredom

Posted 2020-09-29 午夜的行人

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.

Input

The first line contains integer n (1?≤?n?≤?105) that shows how many numbers are in Alex‘s sequence.

The second line contains n integers a1, a2, ..., an (1?≤?ai?≤?105).

Output

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

Examples

input

2
1 2

output

2

input

3
1 2 3

output

4

input

9
1 2 1 3 2 2 2 2 3

output

10

Note

Consider the third test example. At first step we need to choose any element equal to 2. After that step our sequence looks like this[2,?2,?2,?2]. Then we do 4 steps, on each step we choose any element equals to 2. In total we earn 10 points.

 

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cmath>
 4 #include<algorithm>
 5 #include<cstdlib>
 6 #include<cstring>
 7 using namespace std;
 8 long long a[100010],ans[100010];
 9 int main()
10 {
11     int n,i,k;
12     cin>>n;
13     for(i=0;i<n;i++){
14         scanf("%d",&k);
15         a[k]++;
16     }
17     ans[1]=a[1];
18     for(i=2;i<=100002;i++){
19         ans[i]=max(ans[i-1],ans[i-2]+i*a[i]);
20     }
21     cout<<ans[100002]<<endl;
22     return 0;
23 }