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 os,sys
def Solver(n):
    if n % 2:
        print("0")
    else:
        ans = 2**(n/2)
        print(ans)

if __name__ == '__main__':
   while True:
       try:
           n = int(raw_input())
           Solver(n)
       except EOFError:
           break