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

SOLUTION: OK

PROBLEM: VTwtMVKmrRvL, WLoVtWtMVKmrDCke

SOLUTION: tMVKmr

PROBLEM: OItMjjXOWMBfvLrNTDolx, FSrjjXOWMBfvLZXADaeuJ

SOLUTION:
jjXOWMBfvL