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 assist you? 
 customer: Can you please help me in reserving a flight from SFO to reach all the places at DEN? 
 agent: Can I know your travelling dates? 
 customer: Thank you, I would like to start on Nov 2nd and return on Nov 4th. 
 agent: May I know your connection limit? 
 customer: I prefer a flight with single connection. 
 agent: Do you need any other preference? 
 customer: I don't have any other preferences. 
 agent: Can I know your name please? 
 customer: Nicole Mitchell is my name. 
 agent: Sorry to inform you that there are no flights available. 
 customer: Ok, not an issue. Anyways, thank you for the information. 
 agent: Thank you for contacting us.
Output:
no_flight