user: Question: If the season is before 2000, the runner up was north melbourne, and it's the pre-season cup, what's the sum of attendees?
Columns: ['Season', 'Premier', 'Runner Up', 'Score', 'Venue', 'Attendance', 'Premiership']
Types: ['real', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: [1984.0, 'Essendon', 'Sydney Swans', '13.11 (89) – 5.8 (38)', 'Waverley Park', 30824.0, 'Night series']
SQL:

assistant: SELECT SUM("Attendance") FROM "Table" WHERE "Premiership" = 'pre-season cup' AND "Runner Up" = 'north melbourne' AND "Season" < 2000.0;