CREATE TABLE institution (institution_id VARCHAR(255), building_id VARCHAR(255)); CREATE TABLE building (building_id VARCHAR(255), floors VARCHAR(255)); CREATE TABLE protein (institution_id VARCHAR(255))
How many proteins are associated with an institution in a building with at least 20 floors?
    
SQL: SELECT COUNT(*) FROM institution AS T1 JOIN protein AS T2 ON T1.institution_id = T2.institution_id JOIN building AS T3 ON T3.building_id = T1.building_id WHERE T3.floors >= 20