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.Scanner;


/**
 *
 * @author ������
 */
public class JavaClass {
    public static void main(String[] args)
    {
Scanner in=new Scanner(System.in);
int n=in.nextInt();
double x=Math.sqrt(n);
double s=Math.floor(x);
int e=(int)s;
int perimeter=e*4;
int diff=(e+1)*(e+1)-e*e;
if (n-e*e>0&&n-e*e<=diff/2)
    perimeter+=2;
else if (n-e*e>diff/2)
    perimeter+=4;

System.out.println(perimeter);
    }}

