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: Hello. 
 agent: Hello, how can I help you today? 
 customer: Can you please help me to book a flight ticket from ORD to SEA? 
 agent: Sure, please share your planned travel dates? 
 customer: My trip dates are Apr 10 to Apr 12. 
 agent: Any other requirements to be met? 
 customer: No. 
 agent: Can I have your name please? 
 customer: My name is Shirley Hall. 
 agent: Frontier Airline flight 1003 available with connection limit 0 and fare is 200, shall I confirm this economy class flight? 
 customer: Ok, please proceed. 
 agent: Ok, your ticket has been booked. 
 customer: Thank you. 
 agent: Thank you for reaching us.
A:
book