#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;

// #define int long long

#define pii pair<int, int>
#define pll pair<ld, ld>
#define vi vector<int>
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define mp make_pair
#define pb push_back
#define sz(v) (int)(v).size()
// #define endl '\n'

const ld eps = 1e-8;
const ll mod = 1e9 + 7;
const int inf0 = 1e9 + 10;
const ll inf = 2e18 + 10;

void solve();

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
#ifdef LC
    freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
#endif
    cout << fixed << setprecision(20);
    int t = 1;
    //cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}

void solve() {
    int n; cin >> n;
    vector<int> a(n);
    for(int i = 0; i < n; i++)
        cin >> a[i];
    sort(rall(a));
    ll ans = 0;
    int k = n / 3;
    for(int i = 0; i < k; i++)
        ans += a[2 * i + 1];
    cout << ans << endl;
}

// g++ -DLC -o a a.cpp && ./a