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

Example Input: BdqUloJanutXoOyfLsuA, NRDloJanutXoOQY
Example Output: loJanutXoO

Example Input: HorIyjpfBFmKZQUIEoP, AcWOaOgVPmyjpfBFmKZQPFYiI
Example Output: yjpfBFmKZQ

Example Input: WMsYsClpaGVaUv, kwpsClpaGgfrsN
Example Output:
sClpaG