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 ProblemB {
   public static void main(String[] args) {
       Scanner scanner = new Scanner(System.in);
       int N = scanner.nextInt();
       int square = (int) Math.floor(Math.sqrt(N));
       int squareArea = 4 * square;
       int rest = N - square * square;
       int additionalBlocks = 0;
       if (rest > 0)
    	   additionalBlocks += 2;
       if (rest > square)
    	   additionalBlocks += 2;
       int result = squareArea + additionalBlocks;
       System.out.println(result);
   }
}