AA 3436 then UA 3376 at O'Hare
Rochester (ROC) → Chicago → St Louis
Timetable, Chicago time
16:24AA 3436 from Rochester (ROC) at the gate
11:00UA 3376 to St Louis leaves the gate
18 h 36 apart on the timetable, overnight
UA 3376 leaves 18 h 36 after AA 3436 arrives on the timetable: more than half a day, so not a connection we count.