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_55 (year INTEGER, chassis VARCHAR)
### Question:
What year was a Rial Arc2 chassis used?
### Answer:
SELECT SUM(year) FROM table_name_55 WHERE chassis = "rial arc2"