How many female clients' accounts are in the region of South Bohemia?
Female refers to gender = 'F'; A3 contains the region 'south Bohemia'
SELECT COUNT(T1.client_id) FROM client AS T1 INNER JOIN district AS T2 ON T1.district_id = T2.district_id WHERE T1.gender = 'F' AND T2.A3 = 'south Bohemia'