How many 3rd ru does Canada have?
CREATE TABLE table_21791 (
    "Rank" real,
    "Country" text,
    "Miss United Continent" real,
    "Virreina" real,
    "1st RU" real,
    "2nd RU" real,
    "3rd RU" real,
    "4th RU" real,
    "Semifinalists" real,
    "Total" real
)
SELECT COUNT("3rd RU") FROM table_21791 WHERE "Country" = 'Canada'
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: How many 3rd ru does Canada have? ### Input: CREATE TABLE table_21791 (
    "Rank" real,
    "Country" text,
    "Miss United Continent" real,
    "Virreina" real,
    "1st RU" real,
    "2nd RU" real,
    "3rd RU" real,
    "4th RU" real,
    "Semifinalists" real,
    "Total" real
) ### Response: SELECT COUNT("3rd RU") FROM table_21791 WHERE "Country" = 'Canada'