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.FileNotFoundException;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;

public class Main {
	
	
	public static void main(String[] args) throws Exception {
        new Main();
    }
	
	int n;
	
	public Main() throws Exception{
		Scanner sc = new Scanner(System.in);
//		Scanner sc = new Scanner(new FileReader("input"));
		
		n = sc.nextInt();
		
		int k = 0;
		
		for (int i=0;true;i++){
			
			if (i * i >= n){
				k = i;
				break;
			}
			
		}
		

		
		if (k * (k-1) >= n){
			System.out.println(  2 * k + 2 * (k-1));
		} else {
			System.out.println(  4 * k);			
		}
		
		
		
		
		
		
        sc.close();
	}
	
	
	
	void printArr(int[] arr){
		System.out.println();
		for(int i=0;i<arr.length;i++){
			System.out.print(arr[i] + " ");
		}
		System.out.println();

	}
	
	
	
	
	
	
	
	
}
