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: What meetings do I have this week with Sarah?
Example Output: user

Example Input: Here are some times when you and Carl are free.
Example Output: agent

Example Input: thanks
Example Output:
user