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.
# -*- coding: utf-8 -*-
"""
Created on Tue Jun 11 18:14:57 2019

@author: Hamadeh
"""

class cinn:
    def __init__(self):
        self.x=[]
    def cin(self,t=int):
        if(len(self.x)==0):
            a=input()
            self.x=a.split()
            self.x.reverse()
        return self.get(t)
    def get(self,t):
        return t(self.x.pop())
    def clist(self,n,t=int): #n is number of inputs, t is type to be casted
        l=[0]*n
        for i in range(n):
            l[i]=self.cin(t)
        return l
    def clist2(self,n,t1=int,t2=int,t3=int,tn=2):
        l=[0]*n
        for i in range(n):
            if(tn==2):
                a1=self.cin(t1)
                a2=self.cin(t2)
                l[i]=(a1,a2)
            elif (tn==3):
                a1=self.cin(t1)
                a2=self.cin(t2)
                a3=self.cin(t3)
                l[i]=(a1,a2,a3)
        return l
    def clist3(self,n,t1=int,t2=int,t3=int):
        return self.clist2(self,n,t1,t2,t3,3)
    def cout(self,i,ans=''):   
        if(ans==''):
            print("Case #"+str(i+1)+":", end=' ')
        else:
            print("Case #"+str(i+1)+":",ans)
    def printf(self,thing):
        print(thing,end='')
    def countlist(self,l,s=0,e=None):
        if(e==None):
            e=len(l)
        dic={}
        for el in range(s,e):
            if l[el] not in dic:
                dic[l[el]]=1
            else:
                dic[l[el]]+=1
        return dic
    def talk (self,x):
        print(x,flush=True)
    def dp1(self,k):
        L=[-1]*(k)
        return L
    def dp2(self,k,kk):
        L=[-1]*(k)
        for i in range(k):
            L[i]=[-1]*kk
        return L
c=cinn()
n=c.cin()
if(n%2):
    print(0)
else:
    print(int(2**(n/2)))