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>
//package problems;
import java.util.Scanner;

public class lazySecurityGuard
{
    public static void main(String[] args)
    {
        Scanner rdr = new Scanner(System.in);
        int numBlocks = rdr.nextInt();
        int maxSquare = (int)Math.pow(numBlocks, 0.5);
        int rows = (int)(numBlocks/maxSquare);
        int remainder = numBlocks%(rows*maxSquare);
        if(remainder > 0)
        {
            remainder = 1;
        }
        System.out.println(rows*2 + maxSquare*2+remainder*2);
    }
}
