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: Hello. 
 agent: Hello, how may I help you? 
 customer: I am John Martinez, can you help me in booking my flight ticket to LGA from AUS? 
 agent: Sure, could you please provide your travelling dates to search for the flight? 
 customer: Sure, My travelling dates are June 30 and July 2. 
 agent: Do you have any requirements? 
 customer: I need to departure from my source location in the evening. 
 agent: May I know your class preference? 
 customer: I am comfortable with any of the class. 
 agent: Sorry, no flight is available for you as per your requests. 
 customer: Not a problem, anyways thank you for the information. 
 agent: Thank you for reaching us.
Student:
no_flight