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>
/*
 * http://codeforces.com/problemset/problem/859/B
 */

/*  Basic import definitions    */
    import java.util.*;
    import java.math.BigInteger;
    import java.util.LinkedList;

/*  Basic Class definitions*/
    public class lazyGuard
    {
        public static void main(String[] args) 
        {
            Scanner sc = new Scanner(System.in);

            int i , j , k;
            int T,N;
            j=0;
            T = Integer.parseInt(sc.next());
            i = (int)Math.sqrt(T);
            j = T-i*i;
            if(i*i == T)
                k = 4*i;
            else if(j<=i)
            {
                k = 4*i + 2;
            }
            else
            {
                k = 4*(i)+4;
                
            }
            System.out.println(k);
        }
	}