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".

Will Susan be at the retirement party?
user

Please do not cancel it at this time.
user

I have a meeting with Elli coming up this Saturday at 3 pm

user