#include <bits/stdc++.h> using namespace std; int main() { ios::sync_with_stdio(false); cin.tie(NULL); int n, a, i = 0, t = 0; cin >> n; vector<int> b(n); for (int i = 0; i < n; i++) cin >> b[i]; sort(b.begin(), b.end()); a = n % 3; while (i < a && i < n) { t += b[i]; i++; } while (i < n) { t += b[i+1] + b[i+2]; i += 3; } cout << t << '\n'; return 0; }