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.*;
 
 
 
public class test {
 
    public static void main(String[] args)  {
        Scanner scanner = new Scanner(System.in);
        int numberOfBlocks = scanner.nextInt();
		int circuit = -1;
        int findThatHasSquare = numberOfBlocks;
		if(Math.sqrt(findThatHasSquare)%1 == 0){
			circuit = (int) Math.sqrt(findThatHasSquare) * 4;
		}
		else{
			findThatHasSquare = numberOfBlocks;
			while(true){
				if(Math.sqrt(findThatHasSquare)%1 == 0){
					break;
				}
				findThatHasSquare--;
			}
		}
		if(circuit == -1){
    		int sqrt = (int) Math.sqrt(findThatHasSquare);
    		circuit = sqrt * 4;
    		int restBlocks = numberOfBlocks - findThatHasSquare;
    		while(true){
    			if(restBlocks-sqrt > 0){
    				restBlocks =- sqrt;
    				circuit += 2;
    			}	
    			else{
    				circuit += 2;
    				break;
    			}
    		}
		}
		System.out.println(circuit);	
    }
}