import java.io.*;
import java.util.*;

public class delivery_mb_int {
    public static void main(String[] args) throws IOException {
        try (BufferedReader in = new BufferedReader(new InputStreamReader(System.in))) {
            int n = Integer.parseInt(in.readLine());
            int[] data = new int[n];
            StringTokenizer st = new StringTokenizer(in.readLine());
            for (int i = 0; i < n; ++i) {
                data[i] = Integer.parseInt(st.nextToken());
            }
            Arrays.sort(data);
            int k = n / 3;
            int result = 0;
            for (int i = 0, j = n; i < k; ++i) {
                --j;
                result += data[--j];
            }
            System.out.println(result);
        }
    }
}