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 Owners (first_name VARCHAR, name VARCHAR); CREATE TABLE Dogs (first_name VARCHAR, name VARCHAR); CREATE TABLE Professionals (first_name VARCHAR, name VARCHAR)
### Question:
Which first names are used for professionals or owners but are not used as dog names?
### Answer:
SELECT first_name FROM Professionals UNION SELECT first_name FROM Owners EXCEPT SELECT name FROM Dogs