How many frequencies have a line of East London and destination of Crystal Palace?
CREATE TABLE table_name_18 (
    frequency__per_hour_ VARCHAR,
    line VARCHAR,
    destination VARCHAR
)
SELECT COUNT(frequency__per_hour_) FROM table_name_18 WHERE line = "east london" AND destination = "crystal palace"
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 frequencies have a line of East London and destination of Crystal Palace? ### Input: CREATE TABLE table_name_18 (
    frequency__per_hour_ VARCHAR,
    line VARCHAR,
    destination VARCHAR
) ### Response: SELECT COUNT(frequency__per_hour_) FROM table_name_18 WHERE line = "east london" AND destination = "crystal palace"