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

[EX Q]: cjDuPZOHjystHnF, okWVdUDuPZOHjSCaEecP
[EX A]: DuPZOHj

[EX Q]: zbSNNVc, agSNNtOQ
[EX A]: SNN

[EX Q]: XTZKnAtqvCNrFhl, CtPCzFnAtqvCNwEXIRHP
[EX A]:
nAtqvCN