Among the flights with air carrier named Republic Airline, how many of the flights have departure delay of 30 minutes and above?
Republic Airline refers to Description which contains 'Republic Airline'; departure delay of 30 minutes and above refers to DEP_DELAY > 30;
SELECT COUNT(*) FROM `Air Carriers` AS T1 INNER JOIN Airlines AS T2 ON T1.Code = T2.OP_CARRIER_AIRLINE_ID WHERE T1.Description LIKE '%Republic Airline%' AND T2.DEP_DELAY > 30