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.Scanner;

import static java.lang.StrictMath.ceil;
import static java.lang.StrictMath.sqrt;
import static java.lang.System.out;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        if (n <= 3) {
            if (n == 1)
                out.print(4);
            else {
                if (n == 2)
                    out.print(6);
                else
                    out.print(8);
            }
        } else {
           int square = (int) sqrt(n);
           int p = 4 * square;
           int delta = n - square * square;
           int temp = (int) ceil(((double)(((double)delta) / ((double)square))));
           p += 2 * temp;
           out.print(p);
        }
    }
}