def first_Digit(n) :
    import math 
     
    fact = 1
    for i in range(2,n + 1) : 
        fact = fact * i 
        while (fact % 10 == 0) :  
            fact = int(fact / 10) 
    while (fact >= 10) : 
        fact = int(fact / 10) 
    return math.floor(fact) 
def count_ways(n):
	 
	A = [0] * (n + 1) 
	B = [0] * (n + 1) 
	A[0] = 1
	A[1] = 0
	B[0] = 0
	B[1] = 1
	for i in range(2, n+1): 
		A[i] = A[i - 2] + 2 * B[i - 1] 
		B[i] = A[i - 1] + B[i - 2] 
	return A[n] 