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

SOLUTION: sblwU

PROBLEM: eeoJEtGHPDvHck, ezPGHPDvHSf

SOLUTION: GHPDvH

PROBLEM: kzRLfsF, iQRLfwo

SOLUTION:
RLf