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