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_13836704_7 (transit_passengers VARCHAR, airport VARCHAR)
### Question:
How many different total number of transit passengers are there in London Luton?
### Answer:
SELECT COUNT(transit_passengers) FROM table_13836704_7 WHERE airport = "London Luton"