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

[EX Q]: pIkAtJHVcvzzZVz, btWerNSHVcvzzZTz
[EX A]: HVcvzzZ

[EX Q]: dxqZUOvRprXyFfjQfTWBhR, biSVjOvRprXyFfDtuFWQ
[EX A]: OvRprXyFf

[EX Q]: uVXzoYsuCYKfTfc, vgrWYqoYsuCYynR
[EX A]:
oYsuCY