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: Hi. 
 agent: Hello. How can I assist you today? 
 customer: I am Carol Harris. I want to book a ticket from MSP to BOS, can you help me? 
 agent: Sure, can you please share your travel dates? 
 customer: My travel dates are 08/15 and 08/17. 
 agent: Do you have any class preference? 
 customer: I am comfortable with any class. 
 agent: May I know your connection limit? 
 customer: I need a single connection. 
 agent: Is there any requirement that you are looking for? 
 customer: My departure time is afternoon. 
 agent: Carol Harris, I am sorry to inform you that there is no flight available at your request.
no_flight