#include <bits/stdc++.h>
using namespace std;

int main(){
  int n; scanf("%d",&n);
  static int v[1000000]; for (int i=n; i--;) scanf("%d",&v[i]);
  sort(v,v+n);

  int res=0;
  for (int i=n,j=n/3; i-=2, j--;){
    res+=v[i];
  }
  printf("%lld\n",res);
}