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

SOLUTION: VLbQhBx

PROBLEM: fWJdaAfOCfejXZvidHM, gOpfOCfejXZbtLvSLZI

SOLUTION: fOCfejXZ

PROBLEM: vwubvB, hIubyu

SOLUTION:
ub