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;
import java.util.StringTokenizer;

public class Main {
	static BufferedReader reader = null;
	static StringTokenizer tokenizer = null;
	static PrintWriter writer = null;

	static String nextToken() throws IOException {
		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
			tokenizer = new StringTokenizer(reader.readLine());
		}
		return tokenizer.nextToken();
	}

	static int nextInt() throws NumberFormatException, IOException {
		return Integer.parseInt(nextToken());
	}

	static double nextDouble() throws NumberFormatException, IOException {
		return Double.parseDouble(nextToken());
	}

	static long nextLong() throws NumberFormatException, IOException {
		return Long.parseLong(nextToken());
	}

	public static void main(String[] args) throws IOException {
		reader = new BufferedReader(new InputStreamReader(System.in));
		writer = new PrintWriter(System.out);
		banana();
		reader.close();
		writer.close();
	}

	static void banana() throws NumberFormatException, IOException {
		int n = nextInt();
		double d = Math.sqrt(n - 0.0001);
		int a = (int) d + 1;
		if (a * (a - 1) < n) {
			writer.println(2 * 2 * a);
		} else {
			writer.println(2 * (a + a - 1));
		}
	}
}
