Definition: 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, myself Samuel Harris. 
 agent: Hello. How can I help you? 
 customer: Can you please help me to book a direct flight from BOS to JFK? 
 agent: May I know your travelling dates please? 
 customer: My travel dates are from 10/10 to 10/12. 
 agent: There is no direct flight available from BOS to JFK. 
 customer: No problem, thank you for checking. 
 agent: Welcome.
Output:
no_flight