user: Question: For the game against the San Francisco 49ers what was the total attendance?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'real']
Sample row: [1.0, 'September 17, 1967', 'at Baltimore Colts', 'L 38-31', 56715.0]
SQL:

assistant: SELECT SUM("Attendance") FROM "Table" WHERE "Opponent" = 'San Francisco 49ers';