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

SOLUTION: OvLaZ

PROBLEM: YHLJZrFQ, aSLJZQuo

SOLUTION: LJZ

PROBLEM: tNgMfsgr, gbnygMfsWfD

SOLUTION:
gMfs