You will be given a definition of a task first, then some input of the task.
You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.

Sentence1: No, I'm afraid there aren't. Sentence2: Could you look for something that isn't a guesthouse then? Sentence3: Are there any 4 star guesthouses in the north available? Sentence4: I guess I will take the guest house. Sentence5: I'm sorry, but I'm afraid we'll need to try different criteria. Would you be willing to change what part of town you stay in, or the star rating you need? Sentence6: I'm also looking for a hotel to stay in. I need to make sure it's a hotel and not a guesthouse, with a star of 4. Sentence7: i want to go to a park Sentence8: I have three 4 star hotels. what are or price range do you prefer? Sentence9: Yes, please, for 6 people, for 4 nights, starting Wednesday. Sentence10: There are no hotels that meet your requirements. Sentence11: the hotel by 14:45. Sentence12: I'm sorry but there are no parks in the area of your hotel. Sentence13: i aslo want to book a taxi to commute between the two places. Sentence14: I'm sorry, I don't have any 4 star hotels in the north. Would another area be ok, or should I check other star rating options? Sentence15: anywhere is fine. May I get a postcode ? Sentence16: But I said I would take the guesthouse. Sentence17: Okay, Do I need to book that for you? Sentence18: The price doesn't matter. I do want it to be in the north area of town though. Sentence19: There are 5 different parks. Postcodes are CB21JF, CB18DW, CB46AZ, CB22AD, and CB223AE. Sentence20: I'm sorry, but I don't think we determined which park you wanted to visit. Where will you be departing from? Sentence21: Sure, there are a few. What part of town do you prefer? Sentence22: I'm so sorry about that. You are booked at the Acorn Guest Lodge. Reference number is : R68P0A12 . Question: Who has spoken the sentence 18? (A) User (B) System
Output:
Answer: (A) User