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 Tvs {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int num = (int)java.lang.Math.sqrt(n);
		int size = num * num;
		if (n - size == 0) {
			System.out.print(num * 4);
		}else if (n - size > 0 && n - size <= num) {
			System.out.print(num * 4 + 2);
		}else if (n - size > num && n - size <= num * 2) {
			System.out.print(num * 4 + 4);
		}
	}
}
 	  			 		  	 				 		  		 		 		