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 may I help you? 
 customer: I am Richard Harris, want to travel from LGA to CLT. Please help me in booking my ticket. 
 agent: Sure, can you share your travel dates please? 
 customer: Sure, my travelling dates are from 05/02 to 05/04. 
 agent: Thanks for waiting. But I am sorry to say that there are no flights available. 
 customer: It's ok, thank you for your help. 
 agent: Thank you.
Output:
no_flight