What is the number of contestants who are aged exactly 18?
CREATE TABLE table_27691 (
    "Country" text,
    "Contestant" text,
    "Age" real,
    "Height (cm)" real,
    "Height (ft)" text,
    "Hometown" text
)
SELECT COUNT("Contestant") FROM table_27691 WHERE "Age" = '18'
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 is the number of contestants who are aged exactly 18? ### Input: CREATE TABLE table_27691 (
    "Country" text,
    "Contestant" text,
    "Age" real,
    "Height (cm)" real,
    "Height (ft)" text,
    "Hometown" text
) ### Response: SELECT COUNT("Contestant") FROM table_27691 WHERE "Age" = '18'