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 whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
public class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		Scanner in =new Scanner(System.in);
		int n=in.nextInt();
		double k=Math.sqrt(n);
		double ce=Math.ceil(k);
		double fl=Math.floor(k);
		int c=(int)ce;
		int f=(int)fl;
		//System.out.println(k+" "+ce+" "+fl);
		if(c==f)System.out.println(4*c);
		else
		{
			if(ce-k>=k-fl)
			{
				int ans=2*f;
				int a=n/f;
				ans+=2*a;
				int re=n%f;
				if(re!=0)
				ans+=2;
				System.out.println(ans);
			}
			else
			{
				int ans=2*c;
				int a=n/c;
				//System.out.println(a);
				ans+=2*a;
				int re=n%c;
				if(re!=0)
				ans+=2;
				System.out.println(ans);
			}
		}
	}
}