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.util.*;

import static java.lang.Math.*;
import static java.lang.System.*;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(in);
        int n = sc.nextInt();
        double rest = sqrt((double) n);
        if (rest - (int) (rest) == 0) out.println((int) rest * 4);
        else {
            int sq = (int) rest * (int) rest;
            if (n - sq <= (int) rest) out.println((int) rest * 4 + 2);
            else out.println((int) rest * 4 + 4);
        }
    }
}