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 table_12159115_3 (series__number VARCHAR, written_by VARCHAR)
### Question:
How many episodes were written only by William N. Fordes?
### Answer:
SELECT COUNT(series__number) FROM table_12159115_3 WHERE written_by = "William N. Fordes"