What's the title of the episode first seen by 18.15 million people in the US?
CREATE TABLE table_22078972_2 (
    title VARCHAR,
    us_viewers__millions_ VARCHAR
)
SELECT title FROM table_22078972_2 WHERE us_viewers__millions_ = "18.15"
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What's the title of the episode first seen by 18.15 million people in the US? ### Input: CREATE TABLE table_22078972_2 (
    title VARCHAR,
    us_viewers__millions_ VARCHAR
) ### Response: SELECT title FROM table_22078972_2 WHERE us_viewers__millions_ = "18.15"