#include <bits/stdc++.h> using namespace std; const int maxn = (int)1e5+5; int n; int c[maxn]; long long sum = 0; int main () { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); cin >> n; for (int i = 1;i <= n; i++) cin >> c[i]; sort (c+1, c+n+1, greater<int>()); for (int i = 1;i <= n; i += 3) { sum += c[i]; if (i+1 <= n) sum += c[i+1]; } cout << sum << "\n"; return 0; }