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 begin {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int K = in.nextInt();
        double b=0;
        int Square=0;
        for (int i = K; i >= 0; i--) {
            b = Math.sqrt(i);
            if (b - (int) b == 0) {
                Square = i;
                break;
            }
        }
        b=Math.sqrt(Square);
        if(K==Square)
        System.out.println((int)(b*4));
        else
            if(K-Square<=b) System.out.println((int)(b*4+2));
        else System.out.println((int)(b*4+4));
    }
}