Write SQL query to solve given problem: How many customers did not rent material at Mike's store?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(T1.customer_id) FROM customer AS T1 INNER JOIN store AS T2 ON T1.store_id = T2.store_id INNER JOIN staff AS T3 ON T2.manager_staff_id = T3.staff_id WHERE T3.first_name != 'Mike'