F9 4567 then UA 655 at Denver
St Louis → Denver → Las Vegas
Timetable, Denver time
21:30F9 4567 from St Louis at the gate
19:40UA 655 to Las Vegas leaves the gate
22 h 10 apart on the timetable, overnight
UA 655 leaves 22 h 10 after F9 4567 arrives on the timetable: more than half a day, so not a connection we count.