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

[Q]: zeuyZKwvIOfx, BlmZKwvspUt
[A]: ZKwv


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


[Q]: PKKpyu, SdKpLo
[A]:
Kp