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_23 (date INTEGER, region VARCHAR, format VARCHAR)
### Question:
WHAT IS THE LOWEST DATE FOR KOREA, IN CD FORMAT?
### Answer:
SELECT MIN(date) FROM table_name_23 WHERE region = "korea" AND format = "cd"