// source problem :
#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define int long long
#define lb lower_bound
#define ub upper_bound
#define MASK(i) (1LL << (i))
const int inf = 1e18;
void ckmax(int& f, int s)
{
f = (f > s ? f : s);
}
void ckmin(int& f, int s)
{
f = (f < s ? f : s);
}
int32_t main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector<int> a(n);
for (int &i : a) cin >> i;
sort(a.rbegin(), a.rend());
int ans = accumulate(all(a), 0LL);
for (int i = 2; i < n; i += 3) ans -= a[i];
cout << ans;
return 0;
}
