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

SOLUTION: fxUdowLL

PROBLEM: CiElmOvTqJGVJkfSaDRzE, EjDJwMyxTvTqJGVJkfluB

SOLUTION: vTqJGVJkf

PROBLEM: WbQJmMaf, bWQJmwB

SOLUTION:
QJm