Instructions: 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
Input: customer: Hi. 
 agent: Hello. How may I help you? 
 customer: Could you please book a flight ticket from DEN to BOS? 
 agent: Sure, I will help you in booking the ticket. May I know your travelling dates please? 
 customer: My trip dates are Sept 20 and Sept 22. 
 agent: Do you have any other specifications? 
 customer: I need a connecting flight. 
 agent: Please help me with your name for booking. 
 customer: I am Brenda Wilson. 
 agent: Sorry for this inconvenience, I could not find any flight with your requirements. 
 customer: Not a problem, thank you. 
 agent: Thank you for reaching us.
Output:
no_flight