#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define endl "\n";
#define vec vector<ll>
#define vecvec vector<vector<ll>>
using namespace std;
/*#define FileName "connect"
string Ghhhh = ".in";
string Ghhhhh = ".out";
ifstream Girdi(FileName + Ghhhh);
ofstream Cikti(FileName + Ghhhhh);
#define cin Girdi
#define cout Cikti*/
bool comp(ll a, ll b){
return a > b;
}
inline void solve(){
ll n;
cin >> n;
vector<ll> arr(n);
ll sum = 0;
for(ll i = 0 ; i < n ; i++){
cin >> arr[i];
sum += arr[i];
}
sort(arr.begin(),arr.end(),comp);
for(ll i = 0 ; i < n ; i++){
if(i % 3 == 2) sum -= arr[i];
}
cout << sum << endl;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
ll t = 1;
//cin >> t;
while(t--){
solve();
}
}
