CF

#include <bits/stdc++.h>

using namespace std;

vector<int> cnt(100001);

int main() {
    int n;
    cin >> n;

    for(int i = 0; i < n; i++)
    {
        int a;
        cin >> a;
        cnt[a]++;
    }

    int m = 100001;

    vector<long long> d(m);
    d[0] = 0;
    d[1] = cnt[1];
    for(int i = 2; i < m; i++) {
        d[i] = max(d[i - 1], d[i - 2] + cnt[i] * i);
    }
    cout << d[m - 1];
}