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.util.Scanner;

public class B {
    private static int K;
    private static int answer = 0;

    public static void main(String[] args) {
        readInput();
        int squareSide = root(K);
        int squareCells = squareSide * squareSide;
        int substarct = K - squareCells;
        if (substarct == 0)
            answer = squareSide * 4;
        else if (substarct <= squareSide) {
            answer = squareSide * 4 + 2;
        }
        else if (substarct > squareSide) {
            answer = squareSide * 4 + 4;
        }

        answer();

    }

    private static void answer() {
        System.out.println(answer);
    }

    private static int root(int x) {
        return (int) Math.pow(x, 0.5);
    }

    private static void readInput() {
        Scanner scanner = new Scanner(System.in);
        K = scanner.nextInt();
    }
}
