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 LazySecurityGuard
{
    
    public static void main(String[] args)
    {
        Scanner input = new Scanner(System.in);
        int cityBlocks = input.nextInt();
        int squareLength = (int)(Math.sqrt(cityBlocks));
        int blocksInSquare = (int)(Math.pow(squareLength, 2));
        input.close();
        
        // adding extra sides for irregular shapes
        int extraBlocks = cityBlocks - blocksInSquare;
        
        if (extraBlocks == 0) {
            System.out.println(squareLength * 4);
        }
        else if (squareLength - extraBlocks >= 0) {
            System.out.println((squareLength * 4) + 2);
        }
        // if extra blocks wrap around to both width and length; any more would cause a bigger perfect square
        else if (squareLength - extraBlocks < 0) {
            System.out.println((squareLength * 4) + 4);
        }
    }
    
}
