TASK DEFINITION: In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
PROBLEM: bSBuJiZniSlZtO, AcuJiZniSRAOAv

SOLUTION: uJiZniS

PROBLEM: XSnVeAjWLFWTgwmf, WsByLAjWLFWnQfl

SOLUTION: AjWLFW

PROBLEM: QKCkECYJuqCHjIFsMCCHauAzaNm, FlgQMSCHjIFsMCCHdKivY

SOLUTION:
CHjIFsMCCH