#include <bits/stdc++.h>
using namespace std;
#define endl "\n"
#define F first
#define S second
#define ll long long
#define ld long double
#define sz(x) (int)x.size()
#define MAXN  10000000
 
#include <bits/stdc++.h>
using namespace std;


void solve(){
    ll n; cin >> n;
    vector <ll> v(n);
    for(auto &x : v) cin >> x;
    sort(v.begin(), v.end());
    deque <ll> d;
    for(int i =0; i < n; i++){
        d.push_front(v[i]);    
    }
    ll ans = 0;
    for(int j = 0; j < n/3; j++){
        d.pop_front();
        d.pop_back();
        ans += d.front();
        d.pop_front();
    }
    cout << ans;
}

signed main(){
	ios_base::sync_with_stdio(0);cin.tie(0);
	//int t; cin>>t; while(t--)
	solve();
 
	return 0;
}