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 Lessons (staff_id VARCHAR); CREATE TABLE Staff (staff_id VARCHAR, first_name VARCHAR)
### Question:
How many lessons taught by staff whose first name has letter 'a' in it?
### Answer:
SELECT COUNT(*) FROM Lessons AS T1 JOIN Staff AS T2 ON T1.staff_id = T2.staff_id WHERE T2.first_name LIKE "%a%"