In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

[EX Q]: eedZoMwKgDhdsgs, kMMwKgDLm
[EX A]: MwKgD

[EX Q]: skZGHS, HsZGge
[EX A]: ZG

[EX Q]: QRPOwtZATjDoJDdRNNSOH, wiafFMwpAjDoJDdRNNuCDZ
[EX A]:
jDoJDdRNN