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: Hi. I am Edward Moore. 
 agent: Hello, what help you are looking for? 
 customer: I want to go for a weekend trip with my friends to Oakland.Can you help me to reach from SFO to OAK? 
 agent: Please share your itinerary dates. 
 customer: I want to depart on 04/28 and return by 04/30. 
 agent: Please stay online for a moment. 
 customer: Sure. 
 agent: Sorry, all tickets are booked for this summer. 
 customer: That's ok. Anyways, thank you for your help. 
 agent: Thank you for connecting us.
Output:
no_flight