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

SOLUTION: elZaW

PROBLEM: YWNPkA, LuNPnN

SOLUTION: NP

PROBLEM: yHxSOv, PpxSed

SOLUTION:
xS