UA 3902 then UA 2744 at Houston
Toronto → Houston → San Francisco
Timetable, Houston time
08:27UA 3902 from Toronto at the gate
08:25UA 2744 to San Francisco leaves the gate
23 h 58 apart on the timetable, overnight
UA 2744 leaves 23 h 58 after UA 3902 arrives on the timetable: more than half a day, so not a connection we count.