Your security guard friend recently got a new job at a new security company. The company requires him to patrol an area of the city encompassing exactly N city blocks, but they let him choose which blocks. That is, your friend must walk the perimeter of a region whose area is exactly N blocks. Your friend is quite lazy and would like your help to find the shortest possible route that meets the requirements. The city is laid out in a square grid pattern, and is large enough that for the sake of the problem it can be considered infinite.

Input

Input will consist of a single integer N (1 ≤ N ≤ 106), the number of city blocks that must be enclosed by the route.

Output

Print the minimum perimeter that can be achieved.

Examples

Input

4


Output

8


Input

11


Output

14


Input

22


Output

20

Note

Here are some possible shapes for the examples:

<image>
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class problem859b implements Runnable {
    StringTokenizer st;
    BufferedReader in;
    PrintWriter out;

    public static void main(String[] args) {
        new Thread(new problem859b()).start();
    }

    public void run() {
        try {
            in = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);
            solve();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            out.flush();
            out.close();
        }
    }

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

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

    long nextLong() throws NumberFormatException, IOException {
        return Long.parseLong(nextToken());
    }

    double nextDouble() throws NumberFormatException, IOException {
        return Double.parseDouble(nextToken());
    }

    void solve() throws NumberFormatException, IOException {

        int n = nextInt();

        double a = Math.ceil(Math.sqrt(n));

        double extra = Math.floor((a - (n/a)))*2;

        double p = 4*a - extra;

        int res = (int) p;

        out.println(res);
    }
}

