CREATE TABLE table_name_8 (attendance INTEGER, season VARCHAR(255), premiership VARCHAR(255), runner_up VARCHAR(255))
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?
    
SQL: SELECT SUM(attendance) FROM table_name_8 WHERE premiership = "pre-season cup" AND runner_up = "north melbourne" AND season < 2000