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]: AeYjeKwZQillzpD, SnqviKwZQillrxuTB
[A]: KwZQill


[Q]: CDOfObLskZQ, JjQeGfObLszgIm
[A]:
fObLs