UA 718 then UA 3900 at San Francisco
Mexico City → San Francisco → Rio De Janeiro
Timetable, San Francisco time
16:44UA 718 from Mexico City at the gatealso AC 5033
16:00UA 3900 to Rio De Janeiro leaves the gate
23 h 16 apart on the timetable, overnight
UA 3900 leaves 23 h 16 after UA 718 arrives on the timetable: more than half a day, so not a connection we count.