CREATE TABLE affected_region (region_id NUMBER, storm_id NUMBER, number_city_affected NUMBER)
CREATE TABLE region (region_id NUMBER, region_code CLOB, region_name CLOB)
CREATE TABLE storm (storm_id NUMBER, name CLOB, dates_active CLOB, max_speed NUMBER, damage_millions_usd NUMBER, number_deaths NUMBER)

How many regions are affected?
SELECT COUNT(DISTINCT region_id) FROM affected_region
SELECT COUNT(DISTINCT "region_id") FROM "affected_region"