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_15 (grid INTEGER, driver VARCHAR, laps VARCHAR)
### Question:
What is the largest grid with a Driver of ralph firman, and a Lap smaller than 18?
### Answer:
SELECT MAX(grid) FROM table_name_15 WHERE driver = "ralph firman" AND laps < 18