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

SOLUTION: MEDTXnE

PROBLEM: YXsgPE, ENsgSO

SOLUTION: sg

PROBLEM: caxrhYZdbwh, GqUnBmxrhYZdebqWf

SOLUTION:
xrhYZd