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.
# kartikay26

from math import *
from collections import *
from itertools import *
from functools import *
from random import *
def getl(t=int): return [t(x) for x in input().split()]
def get(t=int): return t(input())
alphabet = [chr(x) for x in range(ord('a'), ord('z')+1)]
alnum = lambda x: ord(x) - ord('a')

def main():
	n = get()
	if n%2 == 0:
		print(2**(n//2))
	else:
		print(0)

if __name__ == "__main__":
	main()
