import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;

public class delivery_va {
    public static void main(String[] args) {
        new delivery_va().run();
    }

    BufferedReader br;
    StringTokenizer st;
    PrintWriter out;

    public String nextToken() throws IOException {
        while (st == null || !st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }

    public int nextInt() throws IOException {
        return Integer.parseInt(nextToken());
    }

    public void solve() throws IOException {
        int n = nextInt();
        int[] a = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = nextInt();
        }

        Arrays.sort(a);

        int k = n / 3;
        long ans = 0;
        for (int i = 0, j = n - 2; i < k; i++, j -= 2) {
            ans += a[j];
        }

        out.println(ans);
    }

    public void run() {
        try {
            br = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);

            solve();

            out.close();
        } catch (IOException e) {
        }
    }
}