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

[EX Q]: ftvxfhsnJEygzV, JYxSfhsnJnIqkW
[EX A]: fhsnJ

[EX Q]: AedXEOrEgvnzF, TVTEOrEgvxKuJgv
[EX A]: EOrEgv

[EX Q]: UUODATDMJVNXODXvqMo, gtsFWUiADMJVNXODcjCny
[EX A]:
DMJVNXOD