Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_65 (week VARCHAR, opponent VARCHAR)
### Question:
How many weeks has the opponent been san francisco 49ers?
### Answer:
SELECT COUNT(week) FROM table_name_65 WHERE opponent = "san francisco 49ers"