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

[EX Q]: kvutZfcPKzHE, kTKutZfcPTGmU
[EX A]: utZfcP

[EX Q]: YKpdeJQhzyYiPoODACUu, mjmnIlCehzyYiPoOzZ
[EX A]: hzyYiPoO

[EX Q]: jcVuteeZXEtfIFEtn, iCNFeeZXEtfIFEOiCkzZxapZ
[EX A]:
eeZXEtfIFE