Detailed Instructions: 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: Hello. 
 agent: Hello, how may I help you today? 
 customer: Please book a ticket from SEA to SFO to attend Innovation festival to share my ideas. 
 agent:  Sure, can you please mention your departure and arrival dates of your journey? 
 customer: My travelling dates are Dec 1 and Dec 3. 
 agent: Thank you, may I know your name please? 
 customer: Sure, I am Barbara Williams. 
 agent: Sure, is there any another specifications on your trip, so that I can book a ticket as per your wish? 
 customer: Yes, I want a direct flight. 
 agent: Sorry, there is no flight found with your requirement. 
 customer: Ok, Thank you for your help. 
 agent: Welcome, thank you for reaching us.
A:
no_flight