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CREATE TABLE table_name_78 (withdrawn INTEGER, builder VARCHAR, introduced VARCHAR)
### Question:
when was the building withdrawn when the builder was ac cars and was introduced before 1958?
### Answer:
SELECT SUM(withdrawn) FROM table_name_78 WHERE builder = "ac cars" AND introduced < 1958