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 Guard {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner scan = new Scanner(System.in);

        int n = scan.nextInt();
        int square = 0;
        for (int i = 1; i <= 1001; i++) {
            if (i * i > n) {
                square = i - 1;
                break;
            }
        }
        int perim = square * 4;
        int leftOver = n - (square * square);
        if (leftOver > 0) {
            perim += 2;
            leftOver -= square;
        }
        if (leftOver > 0) {
            perim += 2;
        }
        System.out.println(perim);
    }

}
