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
Problem:customer: Hi. 
 agent: Hello. How may I assist you? 
 customer: Could you please book a ticket in business class to Detroit as I want to attend  a pioneer festival? 
 agent: Sure, I will help you. Can I have your airport codes clearly? 
 customer: Sure, PHL and  DTW are my airport codes. 
 agent: When would you like to plan your journey? 
 customer: I want to travel on 2nd Apr and return on 4th Apr. 
 agent: Can I know your connection preference? 
 customer: I prefer a single connecting flight. 
 agent: Do you have any other specifications? 
 customer: No. 
 agent: May I know your name please? 
 customer: My name is Mary Adams. 
 agent: Mary Adams, no flights has been found on your preferences. 
 customer: Not an issue, thank you for your information. 
 agent: Thank you for reaching us.
Solution:
no_flight