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".

Input: Consider Input: I've changed "Staff Meeting" to be Mark.

Output: agent


Input: Consider Input: add dinner with Barack Obama for wednesday at 8pm

Output: user


Input: Consider Input: Add two more hours to Movie Night.


Output: user