user: ### NOW ANSWER:
Question: What week was the opponent the san diego chargers?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'TV Time', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'September 8, 2002', 'Detroit Lions', 'W 49–21', 'FOX 1:00pm', '72,216']
SQL:

assistant: SELECT COUNT("Week") FROM "Table" WHERE "Opponent" = 'san diego chargers';