UA 5355 then UA 1339 at Denver
Salt Lake City → Denver → San Juan
Timetable, Denver time
12:24UA 5355 from Salt Lake City at the gate
09:46UA 1339 to San Juan leaves the gate
21 h 22 apart on the timetable, overnight
UA 1339 leaves 21 h 22 after UA 5355 arrives on the timetable: more than half a day, so not a connection we count.