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
Q: customer: Hi, I am Kimberly Collins. 
 agent: Hello, how can I help you today? 
 customer: To participate in soft adventure sport at Oakland, can you help me to book a connecting flight? 
 agent: Sure, can you please share your airport codes? 
 customer: My airport codes are Chicago, IL - ORD and Oakland, CA - OAK. 
 agent: May I know your departure and return dates? 
 customer: I will return on 08/25 and start on 08/23. 
 agent: Ok, please wait for a while. 
 customer: Sure. 
 agent: Sorry, there are no flights found with your given dates. 
 customer: Ok, thanks for the information. 
 agent: Thank you for opting us.
A:
no_flight