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>
//package memSQL;

import java.util.PriorityQueue;
import java.util.Scanner;

public class area {

	
	public static void main(String agrs[])
	{
		Scanner in = new Scanner(System.in);
		double area = in.nextDouble();
		
		double length = Math.sqrt(area);
		double floor = Math.floor(length);
		double ceil = floor + 1;
		PriorityQueue<Double> queue = new PriorityQueue<Double>();
		
		if(floor * floor >= area)
		{
			queue.add(4 * floor);
		}
		
		if(floor * ceil >= area)
		{
			queue.add((floor+ceil)*2);
		}
		
		if(floor * (ceil + 1) >= area)
		{
			queue.add((floor+ceil + 1)*2);
		}
		
		queue.add(ceil * 4);
		
		double res = queue.poll();
		long result = (long)res;
		System.out.println(result);
	}
}
