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

SOLUTION: EF

PROBLEM: DFRoMPNDAzNgtLsEPseOzC, qykyPjDAzNgtLsEPYTsNrJaNK

SOLUTION: DAzNgtLsEP

PROBLEM: waXOFtmtzpRKqU, DBFtmtzpRKjxvpnPV

SOLUTION:
FtmtzpRK