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 JavaApplication2 {
   
    public static void main(String[] args) {
        
        Scanner in = new Scanner(System.in);    
        int n = in.nextInt();        
        int k = (int) Math.pow(n, 0.5);
        int ans;
        if (k * k == n)
            System.out.println(4 * k);
        else
        {
            k++;
            int r = n / k;
            ans = (k + r) * 2;
            if (n % k > 0)
                ans += 2;
            System.out.println(ans);
        }
    }
}