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

Ex Input:
customer: Hi,. 
 agent: Hello. 
 customer: My name is Elizabeth Wilson. 
 agent: How may I assist you? 
 customer: Can you please book a flight ticket with in the range of 200 from Seattle? 
 agent: Sure, may I know on which dates you would like to travel? 
 customer: Sure, 09/12 - 09/14 are my travelling dates. 
 agent: Help me with the airport codes? 
 customer: My source code is WA - SEA and destination code is Houston, TX - IAH. 
 agent: Sorry, we do not found any flights running in your given details. 
 customer: Ok, not a problem. Thank you. 
 agent: Thank you for reaching us.

Ex Output:
no_flight


Ex Input:
customer: Hello. 
 agent: Hello, how may I assist you? 
 customer: Is it Central Booking Agency? 
 agent: Yes, say what help are you expecting from my side? 
 customer: Can you book a flight ticket from AUS to LGA? 
 agent: Sure, please mention your dates of trip? 
 customer: It's from 02/09 to 02/11. 
 agent: Ok, please hold on for a moment. 
 customer: Ok, take your time. 
 agent: Sorry, there is no flight is available as per your respective details. 
 customer: Ok, no problem. 
 agent: May I know your name please? 
 customer: Sure, my name is Brenda Clark. 
 agent: Thank you for your information. 
 customer: That's ok. 
 agent: You are welcome.

Ex Output:
no_flight


Ex Input:
customer: Hello. 
 agent: Hello. How can I serve you? 
 customer: I am Paul Thompson want to visit Charlotte, can you book a ticket on 08/08 and 08/10? 
 agent: Sure, I can help you. Can I know your preferable airport codes? 
 customer: Sure, I want to travel from DEN to CLT. 
 agent: Do you have any connection limit? 
 customer: Yes, I need a flight with 1 connection. 
 agent: Please wait a while. 
 customer: Ok. 
 agent: Thanks for your time. We found a Hawaiian airline, flight number:1013 and the price is 100. 
 customer: Ok, proceed with my booking. 
 agent: Your flight ticket has been confirmed. 
 customer: Thank you. 
 agent: Thank you for choosing us.

Ex Output:
book