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 may I assist you for today? 
 customer: Samuel Nelson here. I would like you to book a ticket to Houston on the occasion of my sons convocation. 
 agent: Ok, can you tell me your nearest airport codes? 
 customer: My genesis and terminus airport codes are LAX and IAH. 
 agent: Can I know your travelling dates? 
 customer: My trip details are as follows Mar 27 and Mar 29. 
 agent: Give me a moment. 
 customer: Sure. 
 agent: I have found a business class ticket with a price of 700 and 1 connection. 
 customer: Can you check for economy class with cost of 500? 
 agent: Sorry to inform you that there are no flights found with your requirements. 
 customer: No problem, I will find an alternative way. 
 agent: Thank you for contacting our agency.
Output:
no_flight