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 Anon {
     public static void main(String []args){
    	 Scanner in = new Scanner(System.in);
    	 int N = in.nextInt();
    	 int x = (int)Math.floor(Math.sqrt(N));
    	 int y = N - x*x;
    	 int p = 4*x;
    	 if(y == 0) {
    		 System.out.printf("%d", p);
    		 return;
    	 }
    	 else if(y>=1 && y<=x) {
    		 System.out.printf("%d", p+2);
    		 return;
    	 }
    	 else {
    		 System.out.printf("%d", p+4);
    		 return;
    	 }
     }
}