The conversation between human and AI assistant.
[|Human|] What is unique about the NCAA men's basketball tournament in 2023?
[|AI|] The tournament didn't include any top seeded teams in the final four, and included an exceedingly rare upset of a 16th seed over a 1 seed when Purdue lost.
[|Human|] 
What is unique about the NCAA men's basketball tournament in 2023?