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:

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import java.util.*;

public class LazySecurityGuard {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		
		int N = sc.nextInt();
		
		int k = (int) Math.sqrt(N);
		
		int answer =0;
		if(k*k == N)
			answer = 4*k;
		else if(N <= k*(k+1))
			answer = 4*k +2;
		else
			answer = 4*k +4;
		
		System.out.println(answer);
		sc.close();
		
	}

}
