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 Sample {
	
	public static void main(String[] args) {
		
		Scanner kbd = new Scanner(System.in);
		String input = kbd.nextLine();
		int num = Integer.parseInt(input);
		
		double sqroot = Math.sqrt(num);
		double deci = sqroot - Math.floor(sqroot);
		deci = deci * 10;
		
		if (deci < 5 && deci != 0) {
			
			System.out.println((int)(Math.ceil(sqroot) * 4) - 2);
			
		} else {
			
			System.out.println((int)Math.ceil(sqroot) * 4);
			
		}
		
	}
	
}