Codeforces Boredom(260, div1, A)

#include <bits/stdc++.h>
#define int long long

using namespace std;

inline void max_self(int& a, int b) {
    a = max(a, b);
}

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int N;
    cin >> N;
    vector < int > freq(100001);
    for(int i = 0; i < N; ++i) {
        int x;
        cin >> x;
        ++freq[x];
    }
    vector < pair < int , int > > a;
    for(int i = 1; i < 100001; ++i)
        if(freq[i])
            a.emplace_back(i, freq[i]);
    vector < int > dp(a.size());
    for(int i = 0; i < (int)a.size(); ++i) {
        int prev = i - 1;
        if(prev >= 0 && a[prev].first + 1 == a[i].first)
            --prev;
        dp[i] = a[i].first * a[i].second;
        if(prev >= 0)
            dp[i] += dp[prev];
        if(i != 0)
            max_self(dp[i], dp[i - 1]);
    }
    cout << dp[dp.size() - 1];
}