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;
public class B{
     public static void main(String []args){
     	Scanner scan = new Scanner( System.in );
        int n = scan.nextInt();
        System.out.println( solution( n ) );
     }
     private static int solution(int n){
         if( n == 0 ) return 0;
         if( Math.sqrt( n ) % 1 == 0 ) return (int)Math.sqrt( n ) * 4;
         else{
             double sqrt = Math.floor( Math.sqrt( n ) );
             double diff = n - sqrt * sqrt;
             return (int)(sqrt * 4 + 2 * Math.ceil( diff / sqrt ));
         }
     }
}