F9 4567 then UA 5494 at Denver
St Louis → Denver → Amarillo
Timetable, Denver time
21:30F9 4567 from St Louis at the gate
19:10UA 5494 to Amarillo leaves the gate
21 h 40 apart on the timetable, overnight
UA 5494 leaves 21 h 40 after F9 4567 arrives on the timetable: more than half a day, so not a connection we count.