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. 
 customer: David Evans here. 
 agent: How can I help you at this moment? 
 customer: I would like to visit New York for a business conference, can you please help me out with booking of a flight ticket to go there? 
 agent: Sure, I will help you in booking flight ticket. 
 customer: Thank you. 
 agent: Can you please mention your travel dates for booking flight ticket? 
 customer: Sure, I am planning to go on 10/03 and please book my return ticket on 10/05. 
 agent: May I know your preferable airport code names for further process? 
 customer: Sure, my nearest genesis airport code is SEA and my destination airport code is LGA. 
 agent: Please hold on a moment, I will check flight availability in this route. 
 customer: Ok, take your time but try to bring a best flight in my route. 
 agent: Based on your information, Southwest airline is ready to serve you with 1 connection with a minimum fare of 100 is available for you. Shall I proceed with this? 
 customer: That's fine, you can proceed with booking. 
 agent: Your flight ticket is booked successfully, flight number is 1021. 
 customer: Thank you for your assistance in booking of my ticket. Have a nice day. 
 agent: You are welcome.
A:
book