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>
/*
LANG: JAVA
TASK: 
*/

import java.io.*;
import java.util.*;
public class cf2
{
	public static void main(String[] args)
	{
		Scanner c = new Scanner(System.in);
		int N = c.nextInt();
		int num = (int) Math.sqrt(N);
		
		if(N==num*num) 
		{
			System.out.println(4*num); return;
		}
		else
		{
			int resid = N-num*num;
			if(resid<=num)
			{
				System.out.println(4*num+2);
			}
			else
			{
				System.out.println(4*num+4);
			}
		}
	}
}
