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 scan = new Scanner(System.in);

        int blocks = scan.nextInt();
        int squareLength = (int) Math.sqrt(blocks);
        int sqaureBlocks = squareLength * squareLength;
        int remainder = blocks - sqaureBlocks;
        int perimeter = squareLength * 4;

        int side1Blocks, side2Blocks;

        if (remainder < squareLength) {
            side1Blocks = remainder;
            side2Blocks = 0;
        } else {
            side1Blocks = squareLength;
            side2Blocks = remainder - squareLength;
        }

        if (side1Blocks > 0) {
            perimeter += 2;
        }

        if (side2Blocks > 0) {
            perimeter += 2;
        }

        System.out.println(perimeter);
        scan.close();
    }
}
