Q: 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, I am Scott Carter. 
 agent: Hello, how can I help you today? 
 customer: I would like to travel from DCA to DTW. Can you please help me to book a ticket? 
 agent: Sure, kindly assign your travelling dates? 
 customer: My travelling dates will be on 10/04 to 10/06. 
 agent: Ok, any other requirements to met? 
 customer: I need a connecting flight. 
 agent: Ok, please wait for a while. 
 customer: Ok. 
 agent: Thanks for waiting, no flights found with your requested details. 
 customer: Not an issue, thank you. 
 agent: Thank you for opting us.
A:
no_flight