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.io.*;
import java.util.*;
public class guard
{
    public static void main(String args[])throws IOException
    {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        int n=Integer.parseInt(br.readLine());
        int arr[]=new int[1000002+1];
        arr[1]=4;arr[2]=6;arr[3]=8;arr[4]=8;
        int flag=1,c=0,check=2;
        for(int i=5;i<=n;i++)
        {
            if(flag==1)
            {
                if(c==0)
                {
                    arr[i]=arr[i-1]+2;
                    c++;
                }
                else if(c!=check)
                {
                    arr[i]=arr[i-1];
                    c++;
                }
                if(c==check)
                {
                    check++;
                    flag=0;
                    c=0;
                }
            }
            else
            {
                if(c==0)
                {
                    arr[i]=arr[i-1]+2;
                    c++;
                }
                else if(c!=check)
                {
                    arr[i]=arr[i-1];
                    c++;
                }
                if(c==check)
                {
                    //check++;
                    flag=1;
                    c=0;
                }
            }
        }
        System.out.println(arr[n]);
    }
    
}