Among the films starred by Reese West, what is the difference between the films that have store ID of 1 and store ID of 2?
result = subtract(count(film_id where store_id = 1), count(film_id where store_id = 2))
SELECT SUM(IIF(T4.film_id = 1, 1, 0)) - SUM(IIF(T4.film_id = 2, 1, 0)) AS diff FROM film_actor AS T1 INNER JOIN actor AS T2 ON T1.actor_id = T2.actor_id INNER JOIN film AS T3 ON T1.film_id = T3.film_id INNER JOIN inventory AS T4 ON T3.film_id = T4.film_id WHERE T2.first_name = 'Reese' AND T2.last_name = 'West'