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 Question859B {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        int i=1;
        int ans=0;
        while (i*i<=n){
           ans =i*i;
           i++;
        }
        //System.out.println(i-1);
        int k=i-1;
        //System.out.println(k);
        int l=i;
        //System.out.println(l);
        int perimeter=0;
        boolean ok=false;


        if(k*(l)<=n){
            ok=true;
            perimeter=2*(k+l);
           //System.out.println(k + " "+l);

        }
        else {

            perimeter=2*(k+k);
            //System.out.println(k+" "+k);
        }
        //System.out.println(perimeter);
        if(ok){
            if(k*l==n){
                System.out.println(perimeter);
            }
            else {
                System.out.println(perimeter+2);
            }
        }
        else {
            if(k*k==n){
                System.out.println(perimeter);
            }
            else {
                System.out.println(perimeter+2);
            }
        }
    }
}
