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
Input: customer: Hello. 
 agent: Hello, how can I assist you today? 
 customer: I need you to book a flight ticket from SFO to EWR. Please help me. 
 agent: Sure, may I know your connection limit? 
 customer: I would prefer to reach my destination in a direct flight. 
 agent: Can you please share your planned travel dates? 
 customer: April 26 and 28 are my planned travelling dates. 
 agent: Do you have any other requirements? 
 customer: Nothing much to state. 
 agent: May I know your name please? 
 customer: My name is Mark Williams. 
 agent: Sorry, there are no flights found with your given details. 
 customer: That's ok. Thank you. 
 agent: Thank you for opting us.
Output:
no_flight