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 MinPerimeter
{
    public static void main(String args[])
    {
        Scanner obj = new Scanner(System.in);
        int n = obj.nextInt();
        int perimeter = 0;
        int ctr=0;
        int number=0;
        for(int i=0;;i++)
        {
            if(i*i>n)
            {
                if(i*(i-1)<n)
                {
                    number = i*(i-1);
                    perimeter = i*2+(i-1)*2;
                }
                break;
            }
            else
            {
                number = i*i;     
                perimeter = i*2+i*2;
            }
        }
        for(int i=1;i<=n-number;i++,ctr++)
        {
            if(ctr==0)
                perimeter = perimeter+2;
        }
        System.out.println(perimeter);
    }
}