Boredom

#include <iostream>
#include <vector>

#define ll long long

using namespace std;

int main()
{
    ll cant, n;

    cin >> cant;

    vector < ll > v(100001, 0), DP(100001, 0);

    for(ll i = 0; i < cant; i++){
        cin >> n;

        v[n]++;
    }

    DP[1] = v[1];

    for(ll i = 2; i <= 100000; i++)
        DP[i] = max(DP[i - 1], (DP[i - 2] + (i * v[i])));

    cout << DP[100000] << "\n";

    return 0;
}