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

[EX Q]: QaxEaxdouNyyvNAn, wRjWSaxdouNyyrriQiG
[EX A]: axdouNyy

[EX Q]: ARGchkRez, kUwchkZPE
[EX A]: chk

[EX Q]: fjRZtTPbrGFTEBOZPKZlS, eaagjGmkRZtTPbrGFTrQhnueuYmx
[EX A]:
RZtTPbrGFT