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 helloworld {
		public static void main(String args[]){
			Scanner in = new Scanner(System.in);
			int n = in.nextInt();
			int sq = (int)Math.sqrt(n);
			int left = n-sq*sq;
			int ans = sq*4;
			if(left==0)
				System.out.println(ans);
			else{
				if(left<=sq){
					ans+=2;
				}else{
					ans+=4;
				}
				System.out.println(ans);
			}
			
		}
}
