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.IOException;
import java.io.InputStreamReader;

import static java.lang.StrictMath.sqrt;

public class LazyGuard {

    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        int tiles = Integer.parseInt(reader.readLine());
        int sqrt = (int) sqrt(tiles);
        int sq = sqrt * sqrt;
        int left = tiles - sq;
        int perimeter = sqrt * 4;
        if (left == 0) {
            System.out.print(perimeter);
        } else {
            if (left > sqrt) {
                perimeter += 2;
                //left -= sqrt;
            }
            perimeter += 2;
            //perimeter += left;
            System.out.print(perimeter);
        }

    }
}