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 java.util.Scanner;
public class Salamander
{
	public static void main(String args[])
  	{
	  Scanner s = new Scanner(System.in);
	  int x = s.nextInt();
	  double r = Math.sqrt(x);
	  int c = (int)Math.ceil(r);
	  int f = (int)Math.floor(r);
	  if (c*f<x)
	  {		System.out.println(2*(c+f)+2);
	  }
	  else
	  	System.out.println(2*(c+f));

	}
}