def check_Concat(str1,str2):
    
    N = len(str1)
    M = len(str2)
    if (N % M != 0):
        return False
    for i in range(N):
        if (str1[i] != str2[i % M]):
            return False         
    return True
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] 