def find_last_occurrence(A, x):
    
    (left, right) = (0, len(A) - 1)
    result = -1
    while left <= right:
        mid = (left + right) // 2
        if x == A[mid]:
            result = mid
            left = mid + 1
        elif x < A[mid]:
            right = mid - 1
        else:
            left = mid + 1
    return result 
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] 