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 department (head VARCHAR, departmentID VARCHAR)
### Question:
What is the employee id of the head whose department has the least number of employees?
### Answer:
SELECT head FROM department GROUP BY departmentID ORDER BY COUNT(departmentID) LIMIT 1