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.File;
import java.io.FileReader;
import java.io.InputStreamReader;

public class B859 {
    public static void main(String[] args) throws Exception {
        BufferedReader br;
        if (System.getProperty("ONLINE_JUDGE") == null) {
            File f = new File("/home/sisikopf/Workspace/Codeforces/844/src/input");
            br = new BufferedReader(new FileReader(f));
        } else {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        int n = Integer.parseInt(br.readLine());
        int squareSide = findIntegerSqrt(n);
        int diff = n - squareSide*squareSide;
        if(diff == 0) {
            System.out.print(4*squareSide);
        } else if(diff<=squareSide) {
            System.out.print(4*squareSide + 2);
        } else {
            System.out.print(4*squareSide + 4);
        }
    }

    public static int findIntegerSqrt(int n) {
        for(int i = n; n>0; n--) {
            double sqrt = Math.sqrt(n);
            if(sqrt - (int)sqrt == 0)
                return (int)sqrt;
        }
        return -1;
    }

}
