There are 3N participants in AtCoder Group Contest. The strength of the i-th participant is represented by an integer a_i. They will form N teams, each consisting of three participants. No participant may belong to multiple teams.

The strength of a team is defined as the second largest strength among its members. For example, a team of participants of strength 1, 5, 2 has a strength 2, and a team of three participants of strength 3, 2, 3 has a strength 3.

Find the maximum possible sum of the strengths of N teams.

Constraints

* 1 ≤ N ≤ 10^5
* 1 ≤ a_i ≤ 10^{9}
* a_i are integers.

Input

Input is given from Standard Input in the following format:


N
a_1 a_2 ... a_{3N}


Output

Print the answer.

Examples

Input

2
5 2 8 5 1 5


Output

10


Input

10
1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000


Output

10000000000
import java.io.BufferedReader;
import java.io.InputStreamReader;

import java.util.Arrays;
import java.util.Collections;
import java.util.ArrayList;
import java.util.List;
import java.util.HashSet;
import java.io.PrintWriter;
import java.io.OutputStream;
import java.util.Comparator;

public class Main {
    // 標準入力
    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    // 標準入力数値配列用 int
    static int[] inputval() throws Exception {
        String[] strarray = br.readLine().trim().split(" ");
        int[] intarray = new int[strarray.length];
        for (int i = 0; i < intarray.length; i++) {
            intarray[i] = Integer.parseInt(strarray[i]);
        }
        return intarray;
    }

    // 標準入力数値リスト用 int
    static List<Integer> inputIntList() throws Exception {
        List<String> strList = Arrays.asList(br.readLine().trim().split(" "));
        List<Integer> intList = new ArrayList<Integer>();
        for (String elem : strList){
            intList.add(Integer.parseInt(elem));
        }
        return intList;
    }

    // 標準入力数値配列用 integer 降順ソート用
    static Integer[] inputvalInteger() throws Exception {
        String[] strarray = br.readLine().trim().split(" ");
        Integer[] intarray = new Integer[strarray.length];
        for (int i = 0; i < intarray.length; i++) {
            intarray[i] = Integer.parseInt(strarray[i]);
        }
        return intarray;
    }

    public static void main(String[] args) throws Exception {
        // write your code here
        int n = Integer.parseInt(br.readLine());
        Integer [] al = inputvalInteger();
        Arrays.sort(al, Collections.reverseOrder());
        long ans = 0;
        for (int i=0; i<n; i++){
            ans += al[1+2*i];
        }

        System.out.println(ans);

    }

}

