Teacher: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
Teacher: Now, understand the problem? Solve this instance: customer: Hello. 
 agent: Hello, how best I can aid you at this moment? 
 customer: We are going to Washington, but first we should make a plane reservation. Can you please help me with this? 
 agent: Sure, I would like to make a reservation to Washington. 
 customer: Thank you for accepting my request. 
 agent: Could you please help me with your travelling airport codes? 
 customer: Sure, my airport codes are IAD - DCA. 
 agent: At what class, would you like to prefer to travel? 
 customer: I am fine with any class. 
 agent: Do you have any specific time for your journey? 
 customer: Yes, I would like to depart in afternoon time. 
 agent: When you are willing to travel to reach your destination? 
 customer: I have scheduled my trip dates on Nov 9th to 11th. 
 agent: Ok, Do you prefer to travel in a major airlines? 
 customer: I am comfortable with any airline. 
 agent: Thank you for sharing all the required details, please help me with your name. So, I can check the availability of flights. 
 customer: Jack Perez is my name. 
 agent: Please wait for a moment, I will inform you about the flight details as soon as possible. 
 customer: Ok, sure. 
 agent: Thanks for waiting, Jack Perez. 
 customer: Ok. 
 agent: Sorry for the inconvenience, there were no flights moving to your location due to sold out of tickets. 
 customer: It's sad to hear, but no issues at all. Thank you for the best service. 
 agent: Thank you for consulting our chat service. Hope we serve you again.
Student:
no_flight