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.*;

public class LazySecurityGuard {
	
	
	public static void main(String[] args)
	{
		Scanner sc = new Scanner(System.in);
		
		int N = sc.nextInt();
		
		int lower = (int) Math.floor( Math.sqrt(N) ) ;
		
		int remaining = N - (lower * lower);
		
		int perimeter = 0;
		
		if(remaining > lower)
		{
			perimeter = ( lower + 1 ) * 4;
		}
		else if(remaining == 0)
		{
			perimeter = lower * 4;
		}
		else
		{
			perimeter = (lower * 4) + 2;
		}
		
		
		System.out.println(perimeter);
		
		
	}
	
}
