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.*;
import java.util.*;

public class Main {
    
    void solve(BufferedReader br, PrintWriter out) throws IOException{
        int n = Integer.parseInt(br.readLine().trim());
        int k = (int)Math.ceil(Math.sqrt(n));
        int a = (int)n/k;
        int b = (int)n%k;
        if(b==0) {
            out.println((int)(2*a + 2*k));
            return;
        }
        int c = 2*a + 2*k + 2;
        out.println((int)c);
    }
    
    
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(System.out);
        int t = 1;//Integer.parseInt(br.readLine().trim());
        while(t-->0) {
            new Main().solve(br, out);
        }
        br.close();
        out.close();
    }
    
}
