<|im_start|>system
You are a helpful assistant. You first think about the reasoning process in the mind and then provide the user with the answer. You should try to truely solve the question by yourself without cheating.  <|im_end|>
<|im_start|>user
 Eight students from a university are planning to carpool for a trip. Among them, there are two students from each of the grades one, two, three, and four. They will be divided into two cars, A and B, with each car seating four students. The twin sisters from the first grade must ride in the same car. Find the number of ways to arrange the four students in car A such that exactly two of them are from the same grade. Show your work in <think> </think> tags. And return the final answer in <answer> </answer> tags.<|im_end|>
<|im_start|>assistant
Let me solve this step by step.
<think>
user
24
Eight students from a university are planning to carpool for a trip. Among them, there are two students from each of the grades one, two, three, and four. They will be divided into two cars, A and B, with each car seating four students. The twin sisters from the first grade must ride in the same car. Find the number of ways to arrange the four students in car A such that exactly two of them are from the same grade.
test