What is the total number of weeks that the buffalo bills played against the San Diego Chargers?
CREATE TABLE table_name_49 (
    week INTEGER,
    opponent VARCHAR
)
SELECT SUM(week) FROM table_name_49 WHERE opponent = "san diego chargers"
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What is the total number of weeks that the buffalo bills played against the San Diego Chargers? ### Input: CREATE TABLE table_name_49 (
    week INTEGER,
    opponent VARCHAR
) ### Response: SELECT SUM(week) FROM table_name_49 WHERE opponent = "san diego chargers"