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: Hi. 
 agent: Hello. 
 customer: I am Brian Taylor. 
 agent: How can I assist you today? 
 customer: Can you help me in booking from CLT to DTW? 
 agent: Sure, will you mention your travelling dates please? 
 customer: My travelling dates are from Sept 8 to Sept 10. 
 agent: Do you have any limits about flight connections? 
 customer: I need a connecting flight. 
 agent: Do you have any other preferences? 
 customer: My return time is evening. 
 agent: Do you have any preferences about class? 
 customer: No. 
 agent: Please give me a moment. 
 customer: Sure. 
 agent: Thanks for waiting, there is no flights found under your preferable details. 
 customer: Ok, No issues. Thank you. 
 agent: Welcome, have a great day.
Student:
no_flight