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.
'''
##======================================================================================================================================##
   ##         _____       _       _    _    _____   _      _  _    _   _____          _____    ____       ___     ____   ___         ##
      ##     |           / \     | \  / |  |        |      |  |\   |  |     |        |        |    |  |  |   \   |      |   |     ##
         ##  |_____     /   \    |  \/  |  |_____   |      |  | \  |  |    __   ---  |_____   |____|  |  |    |  |___   |___|  ##
      ##           |   /     \   |      |        |  |      |  |  \ |  |     |              |  |       |  |    |  |      |  \      ##
   ##         _____|  /       \  |      |   _____|   \ __ /   |   \|  |_____|         _____|  |       |  |___/   |____  |   \        ##
##======================================================================================================================================##
------------------------------Samsung_Spider------------------------------
'''
n = int(input())
if n % 2 == 0: print(int(pow(2, n / 2)))
else: print(0)