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 _0794LazySecurityGuard {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int n=sc.nextInt();
	
		for(int i=1;i<=1000;i++) {
			for(int j=1;j<=1000;j++) {
				if(Math.abs(i-j)<=1 && (i*j)>=n) {
					System.out.println((i+j)*2);
						return;
}
			}
		}

	}

}
