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.ArrayList;
import java.util.HashMap;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {






      Scanner in=new Scanner(System.in);
      int n=in.nextInt();
//      double w1=Math.sqrt(n);
     
      double w= Math.ceil(Math.sqrt(n));
      double h=Math.ceil(n/w);
      int res=(int)(h+w)*2;
//       double h1=(n/w1);
      
       
        System.out.println(res);
      
      
      
      
      
      
      
      
      
      
      
      
    }
    
}