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.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;

public class Basic {
    static final int four = 4;
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int input = scan.nextInt();
        double value =  Math.sqrt(input);
        if(value % 1 == 0){
            value = value * four;
        }else{
            value = (int) value;
            int valueTemp = (int) value * (int) value;
            if((input - valueTemp) <= value){
                value = (int) value * four + 2;
            }else{
                value = (int) value * four + 4;
            }
        }
        System.out.println((int)value);
        }
}
