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

SOLUTION: FobZE

PROBLEM: OrcQOvMBhmwP, mnWrzcQOvMBnLwI

SOLUTION: cQOvMB

PROBLEM: keCvbwX, jiCvbzdN

SOLUTION:
Cvb