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_25046766_1 (episode_no VARCHAR, written_by VARCHAR)
### Question:
When don inglis and ralph smart are the writers how many episode numbers are there?
### Answer:
SELECT COUNT(episode_no) FROM table_25046766_1 WHERE written_by = "Don Inglis and Ralph Smart"