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

[Q]: HKCoXQsLRtowYJ, PGRzNUQsLRtoLcqkn
[A]: QsLRto


[Q]: MSxTzCpiJAplpzSvLlNJS, oScCpiJAplpNVrqkn
[A]: CpiJAplp


[Q]: ospFRsyAFQTXQ, gyjcdsyAFQTLH
[A]:
syAFQT