i would like a flight between denver and san francisco leaving from denver in the afternoon and arriving at 5 pm it must be a nonstop flight
O O O O O O B-fromloc.city_name O B-toloc.city_name I-toloc.city_name O O B-fromloc.city_name O O B-depart_time.period_of_day O O O B-arrive_time.time I-arrive_time.time O O O O B-flight_stop O