UA 142 then WN 988 at Denver
Tokyo → Denver → Buffalo
Timetable, Denver time
12:15UA 142 from Tokyo at the gate
11:50WN 988 to Buffalo leaves the gate
23 h 35 apart on the timetable, overnight
WN 988 leaves 23 h 35 after UA 142 arrives on the timetable: more than half a day, so not a connection we count.