You will be given a definition of a task first, then some input of the task.
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 help you today? 
 customer: I want to book a flight ticket from Washington so, can you please book a ticket in business class? 
 agent: Yes, I will definitely try my best to help you in booking your flight ticket. Could you please provide your planned dates of journey? 
 customer: My travelling dates are May 12 and May 14. 
 agent: May I know your airport codes? 
 customer: I want to start from IAD to LGA. 
 agent: Do you have any connection limit? 
 customer: I need a connecting flight. 
 agent: At which time you want to travel? 
 customer: I want to return in the evening. 
 agent: Sorry to say, there are no flights available for your desired connection. 
 customer: That's ok, thank you for the response. 
 agent: May I know your name? 
 customer: My name is Michelle Jones. 
 agent: Thanks for reaching us.
Output:
no_flight