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.*;
import java.util.*;
import java.lang.*;
import static java.lang.System.*;
public class A
{
public static void main (String args[]) throws Exception
{
	 Scanner sc=new Scanner(in);
	 int n=sc.nextInt();
	 int x=1;
	 for(int i=1;i>0;i++)
	 {
		 if(i*i>n)
		 {x=i;break;}

	 }

	 x--;
	 long ans=x*4;
	 n=n-x*x;
	 if(n==0)
	 {}
	 else if(n<=x)
	 {
		 ans+=2;
	 }
	 else
	 ans+=4;
	 out.println(ans);

}
}