UA 3876 then UA 767 at O'Hare
Miami → Chicago → Denver
Timetable, Chicago time
14:49UA 3876 from Miami at the gate
14:30UA 767 to Denver leaves the gate
23 h 41 apart on the timetable, overnight
UA 767 leaves 23 h 41 after UA 3876 arrives on the timetable: more than half a day, so not a connection we count.