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.IOException;
import java.io.InputStreamReader;

public class A {
	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		
		String line = br.readLine();
		int n = Integer.parseInt(line);
		
		if(n%2==0){
			int ans = (int)Math.pow(2,(n/2));
			System.out.println(ans);
		}else{
			System.out.println("0\n");
		}
		
		br.close();
	}
}
