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_name_77 (max_aperture VARCHAR, focal_length VARCHAR)
### Question:
What is the maximum aperture of the lens(es) with a focal length of 20mm?
### Answer:
SELECT max_aperture FROM table_name_77 WHERE focal_length = "20mm"