What are the first names of the professors who do not teach a class.
SELECT emp_fname FROM employee WHERE emp_jobcode  =  'PROF' EXCEPT SELECT T1.emp_fname FROM employee AS T1 JOIN CLASS AS T2 ON T1.emp_num  =  T2.prof_num
SELECT emp_fname FROM employee WHERE emp_jobcode  =  'PROF' EXCEPT SELECT T1.emp_fname FROM employee AS T1 JOIN CLASS AS T2 ON T1.emp_num  =  T2.prof_num
[{'EMP_FNAME': 'Anne'}, {'EMP_FNAME': 'Annelise'}, {'EMP_FNAME': 'Doreen'}, {'EMP_FNAME': 'George'}, {'EMP_FNAME': 'Herman'}, {'EMP_FNAME': 'Hermine'}, {'EMP_FNAME': 'James'}, {'EMP_FNAME': 'Melanie'}, {'EMP_FNAME': 'Preston'}, {'EMP_FNAME': 'Ralph'}, {'EMP_FNAME': 'Ronald'}, {'EMP_FNAME': 'Ross'}, {'EMP_FNAME': 'Van'}, {'EMP_FNAME': 'Willa'}]