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
Q: customer: Hi. 
 agent: Hello. 
 customer: I am David Miller. 
 agent: How may I help you today? 
 customer: Can you help me to book a flight to JFK in this week? 
 agent: Sure, may I know your itinerary dates? 
 customer: My travelling dates are 10/27 and 10/29. 
 agent: Ok, can I know your source code please. 
 customer: I would like to start my journey from DTW. 
 agent: Sorry David, no flight's available based on your travelling dates. 
 customer: Ok, no issues. Thank you for your help. 
 agent: Thank you for reaching us.
A:
no_flight