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

SOLUTION: NCGmJElj

PROBLEM: XEvxzelZaWRO, zXIelZaWBUn

SOLUTION: elZaW

PROBLEM: QvtDqzQiSknPbRCG, hVxHdqzQiSknPbumdpNIf

SOLUTION:
qzQiSknPb