/*********************************************************************
AUTHOR: HUMBLE_LOSER

We only fall to rise even higher to heights that we never knew existed!

**********************************************************************/
 
#include <iostream>
#include <cstdio>
#include <cassert>
#include <math.h>
#include <ctime>
#include <bitset>
#include <iomanip>
#include <cstring>
#include <sstream>
#include <algorithm>
#include <stack>
#include <queue>
#include <list>
#include <map>
#include <set>
#include <functional>
#include <vector>
 
using namespace std;
 
#define PI acos(-1)
#define EXP 2.7182818284590452353602874713527
#define endl '\n'
#define ll long long
#define llu long long unsigned
#define ii pair<int,int>
#define vi vector<int>
#define vii vector<ii>
#define vvi vector<vi>
#define vvii vector<vii>
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define xx first
#define yy second
#define sz(v) int(v.size())
#define eps 1e-5
#define forr(i,a,b) for(int i = int(a) ; i<= int(b) ; i++ )
#define rof(i,a,b)  for(int i = int(a) ; i>= int(b) ; i-- )
#define rep(i,n) for(int i=0 ; i<int(n) ; i++ )
#define all(v) (v).begin(),(v).end()
#define inf 0x3f3f3f3f
#define mod 1000000007
#define zero(x) memset(&x,0,sizeof(x))
#define minus(x) memset(&x,0xff,sizeof(x))
#define infinity(x) memset(&x,0x3f,sizeof(x))
#define boost cin.tie(0); ios_base::sync_with_stdio(0); 
#define trace1(x) cerr << #x <<" = "<< x <<endl;
#define trace2(x,y) cerr << #x <<" = "<< x <<" , "<< #y <<" = "<< y <<endl;
#define trace3(x,y,z) cerr << #x <<" = "<< x <<" , "<< #y <<" = "<< y <<" , "<< #z <<" = "<< z <<endl;
#define trace_arr(a,i,n) cerr << #a <<" : " ; forr(_i,i,n) cerr << a[_i] << " "; cerr << endl;
#define trace_mat(a,i,n,j,m) cerr << #a <<" :\n" ; forr(_i,i,n){forr(_j,j,m) cerr << setw(6) << a[_i][_j] << " "; cerr << endl;}cerr<<endl;
#define test_case int __T;cin >> __T; forr(tc, 1 , __T)     
#define code_jam_output cout << "Case #" << tc << ": " 
 
template<class T, class U>
ostream& operator<<(ostream& out, const pair<T, U>& a) {out << "[" << a.first << " " << a.second << "]"; return out;}
template<class T>
ostream& operator<<(ostream& out, const vector<T>& a) {out << "[ "; for (auto &it : a)out << it << " "; out << "]"; return out;}
template<class T>
ostream& operator<<(ostream& out, const set<T>& a) {out << "[ "; for (auto &it : a)out << it << " "; out << "]"; return out;}
template<class T>
ostream& operator<<(ostream& out, const multiset<T>& a) {out << "[ "; for (auto &it : a)out << it << " "; out << "]"; return out;}
template<class T, class U>
ostream& operator<<(ostream& out, const map<T, U>& a) {for (auto &it : a)out << it.first << " -> " << it.second << " | "; return out;}
template<class T, class U>
ostream& operator<<(ostream& out, const multimap<T, U>& a) {for (auto &it : a)out << it.first << " -> " << it.second << " | "; return out;}
 
int x_dir[4] = { -1,0,1,0}; // standard x-y axis NORTH - EAST - SOUTH - WEST
int y_dir[4] = { 0,1,0,-1};

const int max_n = 3e5+100;
int n,k1,k2;
int arr[max_n] , ar2[max_n];


int main() 
{
    cin >> n;
    
    forr(i,0,3*n-1)
        cin >> arr[i];

    sort( arr , arr+3*n , greater<int>() );

    ll ans = 0;
    for(int i = 1,cnt = 0 ; i<3*n and cnt < n ; i++ , i++ , cnt++ )
        ans += arr[i];

    cout << ans;
    return 0;
}


Measured memory_bytes: 1408