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 LSG{
public static void main(String[] args){
Scanner sc=new Scanner(System.in);
int n=sc.nextInt();
int side=0,left=0,ans=0;
for(int i=1;i<=n;i++){
	if(i*i>n) {side=i-1;break;}
	if(i*i==n){side=i;break;}
	}
left = n-(side*side);
ans=4*side;
while(left>0){
	left=left-side;
	ans+=2;
}
System.out.println(ans);
}
}