You have a given integer n. Find the number of ways to fill all 3 × n tiles with the shape described in the picture below. Upon filling, no empty spaces are allowed. Shapes cannot overlap.

<image> This picture describes when n = 4. The left one is the shape and the right one is 3 × n tiles. 

Input

The only line contains one integer n (1 ≤ n ≤ 60) — the length.

Output

Print the number of ways to fill.

Examples

Input


4


Output


4

Input


1


Output


0

Note

In the first example, there are 4 possible cases of filling.

In the second example, you cannot fill the shapes in 3 × 1 tiles.
//JAVA first solution 
import java.io.*; 
import java.util.Scanner;
import java.lang.Math;
public class Roy{
    
public static void main(String [] args){//ISHWAR
    
     Scanner s = new Scanner(System.in); //Tourist_Twin
     int n;
     double b;
     long c;
     n=s.nextInt();
     b=Math.pow(2,n/2);
     Double x = new Double(b); 
     if(n%2==0)
     System.out.println("" + x.longValue());
     else
     System.out.println("0");
     
}
}