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

[EX Q]: IVnbnqBqdPcXfHotUzCYoaGQy, PAlyypBRRBqdPcXfHotpZs
[EX A]: BqdPcXfHot

[EX Q]: ezVsFayUPcrte, lfsFayUMPTqx
[EX A]: sFayU

[EX Q]: tTROCHUo, CXROCSY
[EX A]:
ROC