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 may I help you? 
 customer: I am Emma Baker, I would like to travel to San Francisco, SFO. So will you help me to reserve a flight ticket? 
 agent: Sure. May I know your source airport code please? 
 customer: I am located in New York, the airport I prefer is LGA. 
 agent: Emma, when are you planning your journey? 
 customer: I planned to travel on 01/11 and the return might be on 01/13. 
 agent: Emma, there are no flights available at this moment. 
 customer: It's ok, thank you for searching. 
 agent: Thank you for reaching us. 
 customer: You are welcome.
Student:
no_flight