How many female athletes are from the Philippines?
female athletes refer to id where gender = 'F'; from the Philippines region_name = 'Philippines';
SELECT COUNT(T2.person_id) FROM noc_region AS T1 INNER JOIN person_region AS T2 ON T1.id = T2.region_id INNER JOIN person AS T3 ON T2.person_id = T3.id WHERE T1.region_name = 'Philippines' AND T3.gender = 'F'