A compound of the formula (I): , wherein R1 is cycloalkyl, etc; R2 is (lower) alkoxy, etc; R3 is (lower) alkylene, etc; R4 is (lower) alkylene, etc; R5 is hydroxy. etc; X is "O", "S", "SO", or "SO2"; Y is "CH" or "N"; n is 0 or 1; or pharmaceutically acceptable salts thereof, which are useful as a medicament.