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
Example: customer: Hi. 
 agent: Hello. How can I help you? 
 customer: I would like to change my existing reservation as my plan to go for a holiday trip got postponed. Can you please help me with this? 
 agent: Sure, may I know your name please? 
 customer: My name is Anthony Phillips. 
 agent: Please wait a moment. 
 customer: Sure. 
 agent: Unfortunately there is no reservation found with your given name. 
 customer: Not a problem, thank you for checking. 
 agent: Thank you for choosing us.
Example solution: no_reservation
Example explanation: Here the customer has not asked for any booking, he just wanted to update his already booked flight, so the status would be no_reservation

Problem: customer: Hello. 
 agent: Hello. 
 customer: I am Mary Smith. 
 agent: How can I assist you? 
 customer: I am going to Houston, TX-HOU to purchase a vintage car from a dealer. Can you hold me a ticket? 
 agent: Sure, may I know your source airport code please? 
 customer: My source airport code is Atlanta, GA-ATL. 
 agent: Please provide the travel dates. 
 customer: My travelling dates are from 11/24 to 11/26. 
 agent: Frontier airlines is having a flight on that route with travel charge of 200, shall I proceed for booking? 
 customer: Please proceed for booking. 
 agent: Your ticket has been booked with flight-1002, have a safe journey. 
 customer: Thanks for your help. 
 agent: Thank you for choosing us.

Solution: book