Among the male customers, how many of them come from a place with over 30,000 inhabitants?
SEX = 'Male', over 30,000 inhabitants refer to NHABITANTS_K > 30; place refers to GEOID;
SELECT COUNT(T1.GEOID) FROM Customers AS T1 INNER JOIN Demog AS T2 ON T1.GEOID = T2.GEOID WHERE T1.SEX = 'Male' AND T2.INHABITANTS_K > 30