user: Question: How many different kickoffs happened when the oppenent was at Rhein Fire?
Columns: ['Week', 'Date', 'Kickoff', 'Opponent', 'Final score', 'Team record', 'Game site', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text', 'real']
Sample row: [1.0, 'Sunday, April 4', '4:00 p.m.', 'at Rhein Fire', 'L 25–26', '0–1', 'Arena AufSchalke', 22736.0]
SQL:

assistant: SELECT COUNT("Kickoff") FROM "Table" WHERE "Opponent" = 'at Rhein Fire';