user: Question: How many different kinds of reports are there for races that Juan Manuel Fangio won?
Columns: ['Race Name', 'Circuit', 'Date', 'Winning driver', 'Constructor', 'Report']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['XI Gran Premio Ciudad de Buenos Aires', 'Buenos Aires', '27 January', 'Juan Manuel Fangio', 'Maserati', 'Report']
SQL:

assistant: SELECT COUNT("Report") FROM "Table" WHERE "Winning driver" = 'Juan Manuel Fangio';