You will be given a definition of a task first, then some input of the task.
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

customer: Hi. 
 agent: Hello, how can I aid you? 
 customer: I am Jason Phillips. I want to go for a holiday trip to Chicago, IL-ORD, can you please book me a ticket? 
 agent: Sure, I am here to help you. Can you please let me know your boarding airport code? 
 customer: My boarding airport code is Detroit, MI-DTW. 
 agent: Can I know your travelling dates? 
 customer: My travelling dates are from 05/22 to 05/24. 
 agent: Do you have any specifications? 
 customer: My price limit is 200. 
 agent: Please, wait for a while. 
 customer: I want a single connection in between my journey. Ok. 
 agent: Unfortunately, there were no flights available with your requirements. 
 customer: No problem. Thank you. 
 agent: Thank you for approaching us.
Output:
no_flight