CREATE TABLE employee (emp_fname VARCHAR, emp_num VARCHAR)
CREATE TABLE CLASS (prof_num VARCHAR)
CREATE TABLE department (dept_code VARCHAR, dept_name VARCHAR)
CREATE TABLE professor (emp_num VARCHAR, dept_code VARCHAR)

What is the first names of the professors from the history department who do not teach a class.
SELECT T1.emp_fname FROM employee AS T1 JOIN professor AS T2 ON T1.emp_num = T2.emp_num JOIN department AS T3 ON T2.dept_code = T3.dept_code WHERE T3.dept_name = 'History' EXCEPT SELECT T4.emp_fname FROM employee AS T4 JOIN CLASS AS T5 ON T4.emp_num = T5.prof_num
SELECT "T1"."emp_fname" FROM "employee" AS "T1" JOIN "professor" AS "T2" ON "T1"."emp_num" = "T2"."emp_num" JOIN "department" AS "T3" ON "T2"."dept_code" = "T3"."dept_code" AND "T3"."dept_name" = 'History' EXCEPT SELECT "T4"."emp_fname" FROM "employee" AS "T4" JOIN "CLASS" AS "T5" ON "T4"."emp_num" = "T5"."prof_num"