Detailed Instructions: In this task, you are given a conversation between a flight agent and the customer. You are given 4 options and you need to select the goal of the conversation. It is provided as part of customer's context, which has to be one of the following: `book`: Make a new reservation, `cancel`: Cancel an existing reservation, `no_flight`: No flight found for the customer's preference, `no_reservation`: No reservation / No change / No cancellation was made in the conversation, mostly enquiring details
Q: customer: Hello. 
 agent: Hello, how can I guide you for today? 
 customer: My name is Barbara Clark. I want to book a flight from DCA to SEA, can you please assist me in that? 
 agent: Can you please share on what dates you are willing to travel? 
 customer: I will start on Feb 26th and will return back on Feb 28th. 
 agent: Do you have any airline preferences? 
 customer: I am looking for a normal-cost airline. 
 agent: Do you have any class preferences? 
 customer: No, I don't have. 
 agent: Do you have any other requirements that you are looking for? 
 customer: I want to depart in the evening and return in the afternoon. 
 agent: There is a flight with ticket fare 200 in AA airlines with a stopover in economy class. Is it ok for you? 
 customer: Please proceed with the booking. 
 agent: Your booking is confirmed with flight number 1012. Departure time is 2:00 AM and arrival time is 19:00 PM. 
 customer: Thank you for your help with the booking. 
 agent: Thank you for contacting us, have a nice day.
A:
book