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.io.BufferedReader;
import java.io.InputStreamReader;

public class B {
	public static void main(String[] args) {
		try {
			InputStreamReader converter = new InputStreamReader(System.in);
			BufferedReader in = new BufferedReader(converter);
			int N = Integer.parseInt(in.readLine());
			int square = (int) Math.sqrt(N);
			if (square * square == N) {
				System.out.println(square * 4);
			} else if (square * (square + 1) >= N) {
				System.out.println(2 * (square + square + 1));
			} else {
				System.out.println((square + 1) * 4);
			}
		} catch (Exception e) {
			System.out.println("Error! Exception: " + e);
		}
	}
}
