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.
ll=lambda:map(int,input().split())
t=lambda:int(input())
ss=lambda:input()
lx=lambda x:map(int,input().split(x))
#from math import log10 ,log2,ceil,factorial as fac,gcd
#from itertools import combinations_with_replacement as cs 
#from functools import reduce
#from bisect import bisect_right as br,bisect_left as bl
#from collections import Counter



#for _ in range(t()):
n=t()
if n%2:
    print(0)
else:
    print(2**(n//2))
    
    
                    
    
        
                            
                         
                
        
        
        
        
        
    

        
        
            

    
       
    
                
                        
                        
    
            
