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: Hello. 
 agent: Hello. How can I assist you? 
 customer: I am Sarah Phillips here, I would like to travel from SEA to EWR, can you please help me to book my ticket? 
 agent: Sure, may I know your itinerary dates? 
 customer: Ok, my preferable dates of journey is from 07/14 to 07/16. 
 agent: Please give me a moment to check for available flights. 
 customer: Sure, but make sure that the connections limit is 1. 
 agent: Sorry Sarah, no flight is available on your preferred dates. 
 customer: Ok, no problem. 
 agent: Thank you for contacting us. 
 customer: Thank you for your information.
Output:
no_flight