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 prereq (course_id VARCHAR); CREATE TABLE course (course_id VARCHAR)
### Question:
How many courses that do not have prerequisite?
### Answer:
SELECT COUNT(*) FROM course WHERE NOT course_id IN (SELECT course_id FROM prereq)