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.
n=int(input())
if (n%2==0):
	half=n//2
	print(2**(half))
else:
	print(0)


# h,w=map(int,input().split())
# ar = [[0 for j in range(w)] for i in range(h)]
# for i in range (h):
# 	for j in range(w):
# 		k = int(input())
#         ar[i][j] = k
# i=0
# j=0
# while(i<h):
# 	count=0
# 	while(j<w):
# 		if arr[i][j]=='*':
# 			if 


# for i in range(h):
# 	count=0
# 	for j in range(w):
# 		if(arr[i][j]=='*'):
# 			if arr


