#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define first ff
#define second ss
typedef pair<int, int> pi;
typedef long long int lint;
const int inf = 0x3f3f3f3f;
const int maxn = 1e5 + 5;
lint n;
lint a[maxn];
lint mini;
bool komp(int t1, int t2) {
return t1 > t2;
}
int main ()
{
ios::sync_with_stdio(0);
cin >> n;
for(int i = 0; i < n; ++i)
cin >> a[i];
sort(a, a + n, komp);
// for(int i = 0; i < n; ++i)
// cout << a[i] << " ";
for(int i = 0; i < n; i += 3) {
mini += a[i] + a[i + 1];
}
cout << mini;
return 0;
}