#include<bits/stdc++.h>
using namespace std;
#define int64_t long long
#define mp make_pair
#define pb push_back
#define all(x) (x).begin(), (x).end()
void Solve(void) {
int N; cin >> N;
vector<int> a;
int64_t ans = 0;
for (int i = 1; i <= N; i ++) {
int x; cin >> x;
a.pb(x);
ans += x;
}
// cout << ans << "\n";
sort(a.rbegin(), a.rend());
for (int i = 2; i < N; i += 3) {
ans -= a[i];
}
cout << ans << "\n";
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(0);
int Tests = 1; // cin >> Tests;
while (Tests --) {
Solve();
}
}
