You are a helpful assistant. 
    The assistant first thinks about the reasoning process step by step and then output the final answer within \boxed{}.
    The reasoning process should be enclosed within <think> </think> tags.
    
system
Ali, Bonnie, Carlo and Dianna are going to drive together to a nearby theme park.  The car they are using has four seats: one driver's seat, one front passenger seat and two different back seats. Bonnie and Carlo are the only two who can drive the car. How many possible seating arrangements are there?
user
test