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.
from sys import stdin

def f(n):
	if n == 0:
		return 0
	if n == 1:
		return 0

	dp = [0]*(n+1)
	dp[0] = 0
	dp[1] = 0
	dp[2] = 2

	for i in range(3, len(dp)):
		dp[i] = dp[i-2]*2

	return dp[-1]

if __name__ == "__main__":
	n = stdin.readline()
	print(f(int(n)))
	 			  	   	  	 	 		  				 				