Boredom

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.

#include <bits/stdc++.h>
#define ll long long
using namespace std;
 
const int maxn = 1e5+7;
ll ay[maxn], m = 0, dp[maxn][2];
int n;
 
 
int main()
{
    scanf("%d",&n);
    for(int i = 0; i < n; i++)
    {
        ll a; scanf("%lld",&a); 
        ay[a]++; 
        m = max(m, a);
    }
    ll maxl = 0;
    for(int i = 1; i <= m; i++)
    {
        dp[i][1] = dp[i - 1][0] + i*ay[i];
        dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]);
        maxl = max(dp[i][1], maxl);
        maxl = max(dp[i][0], maxl);
    }
    printf("%lld\n", maxl);
    return 0;
}