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.*;
import java.io.*;
public class B{
   public static void main(String args[]){
   	Scanner sc=new Scanner(System.in);
   	PrintWriter o=new PrintWriter(System.out);
   
   	int n=sc.nextInt();
   	int x=(int)Math.sqrt(n);
   	
    if(x*x==n)
    	o.println(4*x);
    else if(x*(x+1)>=n){
    	o.println(2*(x+1)+2*x);
    }
    else if(x*(x+1)<n)
    	o.println(4*(x+1));
   	//o.println(x);
   	o.flush();
   	o.close();
   }
}