user: Question: How many rounds total were there on may 31?
Columns: ['Round', 'Name', 'Circuit', 'Date', 'Winning driver', 'Winning car']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'International Gold Cup', 'Oulton Park', 'April 9', 'Tony Trimmer', 'Fittipaldi F8']
SQL:

assistant: SELECT COUNT("Round") FROM "Table" WHERE "Date" = 'may 31';