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.
def ii():
  return int(input())
def ss():
  return [x for x in input()]
def si():
  return [int(x) for x in input().split()]
def mi():
  return map(int, input().split())

a = ii()
if a % 2 != 0:
  print(0)
else:
  print(2 ** (a // 2))