The MacKinnon Stakes races took place on how many venues?
CREATE TABLE table_24850630_3 (venue VARCHAR, race VARCHAR)
SELECT COUNT(venue) FROM table_24850630_3 WHERE race = "Mackinnon Stakes"
### Context: CREATE TABLE table_24850630_3 (venue VARCHAR, race VARCHAR) ### Question: The MacKinnon Stakes races took place on how many venues? ### Answer: SELECT COUNT(venue) FROM table_24850630_3 WHERE race = "Mackinnon Stakes"