What is the total number of drivers who have cars constructed by Mercedes-Benz?
CREATE TABLE table_18893428_1 (
    driver VARCHAR,
    constructor VARCHAR
)
SELECT COUNT(driver) FROM table_18893428_1 WHERE constructor = "Mercedes-Benz"
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 drivers who have cars constructed by Mercedes-Benz? ### Input: CREATE TABLE table_18893428_1 (
    driver VARCHAR,
    constructor VARCHAR
) ### Response: SELECT COUNT(driver) FROM table_18893428_1 WHERE constructor = "Mercedes-Benz"