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

[EX Q]: vFuggVITQuctFG, hdCIWWuuggVITQwr
[EX A]: uggVITQ

[EX Q]: ZyrpGdXvvtrKQIxU, CLNGdXvvtrKQDpicfqLdt
[EX A]: GdXvvtrKQ

[EX Q]: tAhZbyvAWpWKCoS, BAFjdvAWpWKAmwkc
[EX A]:
vAWpWK