In this task, you are given an utterance, which is a part of a conversation between a user and an agent. Your job is to detect the speaker. The user usually commands the agent to schedule events, retrieve event information, and check the schedule. While the agent's response is an answer to the user's questions or follow-up questions on the user's command. Answer with "User" or "Agent".

Example Input: Thank you! You've been very helpful
Example Output: user

Example Input: When is the meeting with the lecture?
Example Output: user

Example Input: I can help you with your calendar.
Example Output:
agent