In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

Q: zqRbqwgmqGIAGTeeoGFOSr, RFnLqwgmqGIAGLcEvAWxY

A: qwgmqGIAG
****
Q: HKCoXQsLRtowYJ, PGRzNUQsLRtoLcqkn

A: QsLRto
****
Q: CneScyUGNElxGz, twdgBhScyUGNWRJo

A:
ScyUGN
****