How many nine-digit numbers can be made using each of the digits 1 through 9 exactly once with the digits alternating between odd and even?
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
How many nine-digit numbers can be made using each of the digits 1 through 9 exactly once with the digits alternating between odd and even?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
2880
How many nine-digit numbers can be made using each of the digits 1 through 9 exactly once with the digits alternating between odd and even?
train