UA 3577 then BR 658 at O'Hare
Rochester (ROC) → Chicago → Toronto Pearson
Timetable, Chicago time
14:29UA 3577 from Rochester (ROC) at the gate
11:30BR 658 to Toronto Pearson leaves the gate
21 h 01 apart on the timetable, overnight
BR 658 leaves 21 h 01 after UA 3577 arrives on the timetable: more than half a day, so not a connection we count.