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 {
    public static void main (String[] args) throws java.lang.Exception {
        Output out = new Output();
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st;
        
        st = new StringTokenizer(br.readLine());
        int n = Integer.parseInt(st.nextToken());
        
        int s = (int) Math.sqrt(n);
        
        if (s*s == n) {
            out.println(4*s);
            out.flush();
            return;
        }
        
        int r = n - s*s;
        
        if (r <= s) {
            out.println(4*s + 2);
            
        } else {
            out.println(4*(s+1));
        }
        out.flush();
    }
    
    
    
}


class Output {
    private BufferedWriter out;

    Output() {
        this.out = new BufferedWriter(new OutputStreamWriter(System.out));
    }

    void print(String s) throws IOException {this.out.write(s);}
    void println(String s) throws IOException {this.out.write(s + "\n");}
    void println(long n) throws IOException {this.out.write(n + "\n");}
    void println(int n) throws IOException {this.out.write(n + "\n");}
    void flush () throws IOException {this.out.flush();}
}