Definition: 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: Hello. 
 agent: Hello, how can I guide you today? 
 customer: Can you please help me with booking a flight ticket from OAK to SEA? 
 agent: Can you please share your travelling dates? 
 customer: My travelling dates are from Sept 22-24. 
 agent: Do you have class preference? 
 customer: I am comfortable with any class. 
 agent: Do you need connection limit? 
 customer: I would be comfortable with single stop over. 
 agent: May I know your name? 
 customer: Dennis Moore here. 
 agent: Sorry, no flight found in that route. 
 customer: No problem, thank you for the information. 
 agent: Thank you for choosing us.
Output:
no_flight