user: Question: How many years was the 400 m event in the olympic games?
Columns: ['Year', 'Competition', 'Venue', 'Position', 'Event']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [2005.0, 'European U23 Championships', 'Erfurt , Germany', '2nd', '4 x 400 m relay']
SQL:

assistant: SELECT COUNT("Year") FROM "Table" WHERE "Competition" = 'olympic games' AND "Event" = '400 m';