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.util.*;
import java.io.*;
public class FilingShapes{
	public static void main(String[] args) throws IOException {
	 BufferedReader br=new BufferedReader(new InputStreamReader(System.in)); 
		Scanner sc = new Scanner(System.in);
		int t=1;
		while(t-- >0)
		{
			int n=sc.nextInt();
			int A[]=new int[n+1];
			A[1]=0;  if(n>=1) A[1]=0; if(n>=2)A[2]=2;
			// int B[]=new int[n];
			for(int i=3;i<=n;i++)
				A[i]=2*A[i-2];
			System.out.println(A[n]);
		}
	}
}