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

[EX Q]: ugDpSMRvHM, DDwSMRvxw
[EX A]: SMRv

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

[EX Q]: cvmkZSJtUVzHRmQEv, QnEKSJtUVzdsE
[EX A]:
SJtUVz