Teacher: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
Teacher: Now, understand the problem? Solve this instance: customer: Hello. 
 agent: Hello. How can I help you? 
 customer: Myself Linda Thomas. I want to visit a trip.I just want to book a ticket. 
 agent: Sure. Help me with the full details of journey. 
 customer: My airport codes are from PA-PHL to NV-LAS. 
 agent: May I know the dates? 
 customer: My dates are from 08/09 to 08/11. 
 agent: Sorry, there is no flight found. 
 customer: Ok, thank you for your help. 
 agent: There is a flight with connection 1 and airline is UA. Can I book it? 
 customer: Ok. 
 agent: Your ticket is booked with number 1029. Thank you. 
 customer: Thank you for your help.
Student:
book