// Arup Guha
// 6/15/2023
// Solution to SIUCF CP Final Contest Problem: Shopaholic
// https://open.kattis.com/problems/shopaholic

using namespace std;
#include <bits/stdc++.h>
typedef long long ll;

int main() {

    int n;
    cin >> n;

    // Read in values.
    vector<int> vals(n);
    for (int i=0; i<n; i++)
        cin >> vals[i];

    // Sort in reverse order.
    sort(vals.rbegin(), vals.rend());

    // Add every third, starting at 2.
    ll total = 0;
    for (int i=2; i<n; i+=3)
        total += vals[i];

    // Ta da!
    cout << total << endl;
    return 0;
}