Y8 7520 then OZ 368 at Pudong
Zhengzhou → Shanghai → Seoul
Timetable, Shanghai time
11:50Y8 7520 from Zhengzhou at the gate
01:30OZ 368 to Seoul leaves the gate
13 h 40 apart on the timetable, overnight
OZ 368 leaves 13 h 40 after Y8 7520 arrives on the timetable: more than half a day, so not a connection we count.