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 test {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scanner = new Scanner(System.in);
		
		String input;
		input = scanner.nextLine();
		
		int n = Integer.parseInt(input);
		
		int i, j, ans;
		if (n == 1)
			System.out.println(4);
		else if (n == 2)
			System.out.println(6);
		else if (n == 3)
			System.out.println(8);
		else{
			i = 1;
			while (i * i <= n)
				i++;
		
			i--;
			if (n == i * i)
				System.out.println(4 * i);
			else{
				j = n / i;
				ans = 2 * j + 2 * i;
				if (n % i != 0)
					ans += 2;
				System.out.println(ans);
			}
		}
		
		scanner.close();
	}

}
