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 may I aid you? 
 customer: I am Cynthia Harris. I want to book a ticket from LAX to SEA, can you help me? 
 agent: Sure, may I know your preferred dates of travel? 
 customer: My travel dates are Feb 25 and 27. 
 agent: Do you have any specifications? 
 customer: I want to travel in economy class only. 
 agent: Ok, please wait a minute. 
 customer: I want to return in the morning. 
 agent: Sorry to say that there were no flights found on your route. 
 customer: No problem, thanks for checking. 
 agent: Thank you.
Output:
no_flight