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 java.io.PrintWriter;

public class LazySecurityGuard {

    public static void main(String... args) throws IOException {
        BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(System.out, false);

        int n = Integer.parseInt(read.readLine());
        int core = (int) Math.sqrt(n);
        int remaining = n - (core * core);
        int adjust = 0;

        if (remaining > 0) {
            if (remaining > core) adjust += 4;
            else adjust += 2;
        }

        out.println((core * 4) + adjust);

        out.flush();
        out.close();
        read.close();
    }

}
