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 Problems1{
    public static void main(String[] args) throws IOException {
        FastScanner sc=new FastScanner(System.in);
        int n=sc.nextInt();
        int s=(int)Math.sqrt(n);
        
        if(n==s*s){
            System.out.println(s*4);
        }else{
            int d=n-(s*s);
            if(d<=s){
                System.out.println(s*4+2);
            }else{
                System.out.println(s*4+4);
            }
        }
        
    }
   
        
    
     //__________________________________________________________
    static class FastScanner {
	    BufferedReader br;
	    StringTokenizer st;
            public FastScanner(InputStream i) {
	        br =  new BufferedReader(new InputStreamReader(i));
	        st = new StringTokenizer("");
	    }
	    public String next() throws IOException {
	        if(st.hasMoreTokens())return st.nextToken();
                else st = new StringTokenizer(br.readLine());
	        return next();
	    }
	    public int nextInt() throws IOException {return Integer.parseInt(next());}
	    public long nextLong() throws IOException {return Long.parseLong(next());}
	    public double nextDouble() throws IOException {return Double.parseDouble(next());}
	}
}
  
