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 Boka_Balok {
	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		int n = s.nextInt();

		if (n < 4) {
			int ans1 = 0;
			if (n == 1)
				ans1 = 4;
			else if (n == 2)
				ans1 = 6;
			else if (n == 3)
				ans1 = 8;
			System.out.println(ans1);
			s.close();
			return;

		}

		int root = (int) Math.sqrt((double) n);
		int x = root, y = root;
		for (; (y * x) <= n; y++)
			;
		y--;
		int ans = (2 * x) + (2 * y);
		int baki = n - (x * y);
		if (baki > 0)
			ans += 2;
		System.out.println(ans);
		s.close();
		return;
	}
}