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 input: 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 output: 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
Q: customer: Hi. 
 agent: Hello, how can I guide you today? 
 customer: Can you please help me in reserving a ticket to reach Houston with fare 1000? 
 agent: Sure, I am glad to help you. 
 customer: Thank you. 
 agent: Help me with your airport codes please? 
 customer: My airport codes are from LAS to IAH. 
 agent: On which dates you want me to book a flight ticket for you? 
 customer: Please book a ticket on 01/22 and need to return on 01/24. 
 agent: Thanks for your details, we found a connecting flight with flight number 1019 in Hawaiian airline and fare is of 100. Shall I reserve it? 
 customer: You can reserve it. 
 agent: May I know your good name please? 
 customer: I am Stephen Davis. 
 agent: Your ticket has been confirmed. 
 customer: Thank you for your extendable support. 
 agent: Thank you for choosing us.
A:
book