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 mill (id VARCHAR, architect_id VARCHAR, built_year INTEGER); CREATE TABLE architect (id VARCHAR, architect_id VARCHAR, built_year INTEGER)
### Question:
How many architects haven't built a mill before year 1850?
### Answer:
SELECT COUNT(*) FROM architect WHERE NOT id IN (SELECT architect_id FROM mill WHERE built_year < 1850)