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

[Q]: nhGinCtvLartcMPhJwGRbpZNrq, iQJlFKayEartcMPhJwDRROB
[A]: artcMPhJw


[Q]: HLtkkRnWkgIdqbQH, dWeFUtkkRnWkgIdZhlQh
[A]: tkkRnWkgId


[Q]: lswQTmqMEaHJvWs, GycPHMTmqMEaHJvvd
[A]:
TmqMEaHJv