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 Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        long n = scanner.nextLong();
        long minCubeSide = (long) Math.floor(Math.sqrt(n));
        long minCubeSquare = minCubeSide * minCubeSide;
        long maxCubeSide = minCubeSide + 1;
        long answer = minCubeSide * 4;
        if (minCubeSquare != n) {
            if (n - minCubeSquare <= minCubeSide) {
                answer += 2;
            } else if (n - minCubeSquare == minCubeSide + 1) {
                answer += 4;
            } else {
                answer = maxCubeSide * 4;
            }
        }
        System.out.println(answer);
    }
}