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 products (color_code VARCHAR); CREATE TABLE Ref_colors (color_code VARCHAR)
### Question:
How many colors are never used by any product?
### Answer:
SELECT COUNT(*) FROM Ref_colors WHERE NOT color_code IN (SELECT color_code FROM products)