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.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class FillingShapes {
	static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); 
	public static void main(String [] args) throws IOException
	{	
		int n = Integer.parseInt(reader.readLine());

		if (n % 2 != 0 || n == 0)
		{
			// odd
			System.out.println(0);
			return;
		}
		System.out.println((int) Math.pow(2, (n/2)));
	}
}