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 PrimPrim 
{
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int area = in.nextInt();
		int sqrt = (int)Math.sqrt((double)area);
		
		int base = sqrt * 4;
		int rem = area - sqrt* sqrt;
		if(rem == 0)
		{
			base+=0;
		}
		else if(rem > sqrt)
		{
			base+=4;
		}
		else
		{
			base+=2;
		}
		
		System.out.println(base);
	}
}
