UA 3902 then F9 3229 at Houston
Toronto → Houston → Denver
Timetable, Houston time
08:27UA 3902 from Toronto at the gate
06:40F9 3229 to Denver leaves the gate
22 h 13 apart on the timetable, overnight
F9 3229 leaves 22 h 13 after UA 3902 arrives on the timetable: more than half a day, so not a connection we count.