UA 3852 then AC 738 at San Francisco
Seoul → San Francisco → Toronto
Timetable, San Francisco time
08:46UA 3852 from Seoul at the gate
08:25AC 738 to Toronto leaves the gate
23 h 39 apart on the timetable, overnight
AC 738 leaves 23 h 39 after UA 3852 arrives on the timetable: more than half a day, so not a connection we count.