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>
/*
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 * and open the template in the editor.
 */



import java.util.Scanner;
public class Code_forcces {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Scanner reader = new Scanner(System.in);
        int n = reader.nextInt();
        int b = 0;
        int a = (int)Math.sqrt(n);
        if (n%a > 0){
            b = n/a + 1;
        }
        else {
            b = n/a;
        }
            
        int p = (a+b)*2;       

        System.out.print(p);
        
    }
    
}
