WN 209 then UA 177 at Denver
St Louis → Denver → Rome
Timetable, Denver time
18:50WN 209 from St Louis at the gate
17:30UA 177 to Rome leaves the gate
22 h 40 apart on the timetable, overnight
UA 177 leaves 22 h 40 after WN 209 arrives on the timetable: more than half a day, so not a connection we count.