Definition: 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
Input: customer: Hello. 
 agent: Hello. Can I know your name? 
 customer: Sure, my name is Karen Scott. 
 agent: How can I serve you? 
 customer: I want to go to San Francisco to meet my grand parents, can you book a ticket on 07/18 and 07/20? 
 agent: Sure, I can help you. May I know your travelling airport codes? 
 customer: Sure, I want to travel from DEN to SFO. 
 agent: Do you have any connection limit? 
 customer: Yes, I need a flight with 1 connection. 
 agent: We found a Frontier airline, flight number:1004 and the price is 200. Can I proceed? 
 customer: yes, proceed. 
 agent: Your flight ticket has been confirmed. 
 customer: Thank you. 
 agent: Thank you for picking us.
Output:
book