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. I am Stephanie Carter. 
 agent: Hello. How can I help you? 
 customer: I want to travel from DCA to DEN, can you please help me to find a flight? 
 agent: Sure, can you please provide your travelling dates? 
 customer: My travel dates are 09/09 and 09/11. 
 agent: Do you have any other specifications? 
 customer: Yes, connection must be 0 and price 500. 
 agent: Sorry as per your requested dates there is no flight available with 0 connection limit. 
 customer: It's ok. Thanks for your help. 
 agent: You are welcome.
Output:
no_flight