A3 999 then A3 960 at Athens
Istanbul → Athens → Bucharest
Timetable, Athens time
07:00A3 999 from Istanbul at the gate
06:55A3 960 to Bucharest leaves the gate
23 h 55 apart on the timetable, overnight
A3 960 leaves 23 h 55 after A3 999 arrives on the timetable: more than half a day, so not a connection we count.