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_12 (year INTEGER, points VARCHAR, chassis VARCHAR)
### Question:
How many years was ensign n180b a Chassis with 4 points?
### Answer:
SELECT SUM(year) FROM table_name_12 WHERE points = 4 AND chassis = "ensign n180b"