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"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_13836704_7 (transit_passengers VARCHAR, airport VARCHAR) Question: How many different total number of transit passengers are there in London Luton? [/INST] SELECT COUNT(transit_passengers) FROM table_13836704_7 WHERE airport = "London Luton" </s>