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_1817879_2 (line_s_ VARCHAR, segment_description VARCHAR)
### Question:
How many lines have the segment description of red line mos-2 west?
### Answer:
SELECT line_s_ FROM table_1817879_2 WHERE segment_description = "Red Line MOS-2 West"