UA 3902 then AA 6255 at O'Hare
Rio De Janeiro → Chicago → Sioux Falls
Timetable, Chicago time
17:01UA 3902 from Rio De Janeiro at the gate
13:02AA 6255 to Sioux Falls leaves the gate
20 h 01 apart on the timetable, overnight
AA 6255 leaves 20 h 01 after UA 3902 arrives on the timetable: more than half a day, so not a connection we count.