text: 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 management (department_id VARCHAR); CREATE TABLE department (department_id VARCHAR)
  ### Question:
  How many departments are led by heads who are not mentioned?
  ### Answer:
  SELECT COUNT(*) FROM department WHERE NOT department_id IN (SELECT department_id FROM management)