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.
import java.io.*;
import java.util.*;
public class Two_pointer {
   public static int gcd(int a,int b){
       if(a==0)
           return b;
       else
           return gcd(b%a,a);
   }
    public static void main(String arg[])throws IOException{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        StringBuilder sb=new StringBuilder();
       int n=Integer.parseInt(br.readLine());
       if(n%2==0)
           System.out.println((long)Math.pow(2,n/2));
       else
           System.out.println("0");
   }
}