Given the task definition and input, reply with output. 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

customer: Hello. 
 agent: Hello, how can I assist you now? 
 customer: I would like to attend a meeting at Las Vegas, please help me in booking a ticket from DEN to LAS. 
 agent: Sure, I am happy to help you with that. Can I have your travel dates  please? 
 customer: My planned travel dates are on July 4 and July 6. 
 agent: Ok, please let me know the timings of your journey. 
 customer: I am comfortable with any timings. 
 agent: Do you prefer any specific airlines  to travel? 
 customer: No, thank you for asking. 
 agent: Do you have any other specifications? 
 customer: I prefer a connecting flight. 
 agent: Can I have your good name please to proceed further? 
 customer: Myself Jeffrey Lee. 
 agent: Sorry to inform you that no flight is available to you on your planned dates. 
 customer: Ok, no issues. Thank you for your information. 
 agent: Thank you for choosing us, have a good day.
no_flight