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.*;

public class test
{
    private static Scanner sc = new Scanner(System.in);
    //sc.nextInt()   read int


	public static void main(String[] args)
    {
		int n = sc.nextInt();
		
		int upper = 1000;
		while( (upper-1)*(upper-1) >= n )upper--;
		
		System.out.println(upper*2 + (n+upper-1)/upper*2);
    }
}


/*
2
1

4 11
5 10
6 10
7 11 
8 14 
9 19 
0 21
*/