UA 3905 then SQ 31 at San Francisco
Tokyo Haneda → San Francisco → Singapore
Timetable, San Francisco time
16:33UA 3905 from Tokyo Haneda at the gate
09:40SQ 31 to Singapore leaves the gate
17 h 07 apart on the timetable, overnight
SQ 31 leaves 17 h 07 after UA 3905 arrives on the timetable: more than half a day, so not a connection we count.