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

[EX Q]: mRVieYomZqJXaTDsShCyfPW, ifOAlnptmZqJXaTDsVMqY
[EX A]: mZqJXaTDs

[EX Q]: ljwjMioOwfOltGBaE, TneNGsoOwfOlxnWWW
[EX A]: oOwfOl

[EX Q]: RFHJjdKET, sIJjdKtdKv
[EX A]:
JjdK