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

[EX Q]: oCtWZYdkvZ, pkktWZYdEHMW
[EX A]: tWZYd

[EX Q]: KJswoapnXz, EQswoaFyH
[EX A]: swoa

[EX Q]: ieDeJhLsesSBSNywCeQZkcWnN, CbHLsesSBSNywNYtDXorR
[EX A]:
LsesSBSNyw