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, I am Lisa Baker. 
 agent: Hello, how can I serve you today? 
 customer: I planned to participate in a Horse racing held at New York, NY - EWR, so I need to book a direct flight. 
 agent: Sure, may I know your planned travel dates? Please share me your source point. 
 customer: Sure, my planned dates are on 05/16 to 05/18. My source point is CA - OAK. 
 agent: Sorry to say that, no flights were found with your given details. 
 customer: No problem, thanks for your support. 
 agent: Thank you for reaching us.
Output:
no_flight