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

[EX Q]: ilgSzrcUKLTNLJbMKMKSt, hFXIuUKLTNLJbMKWxSCkDjY
[EX A]: UKLTNLJbMK

[EX Q]: bSBuJiZniSlZtO, AcuJiZniSRAOAv
[EX A]: uJiZniS

[EX Q]: HHRDeCfvwwmLGwSlK, UDpCfvwwmLGXfJogBNT
[EX A]:
CfvwwmLG