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

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

[EX Q]: DFRoMPNDAzNgtLsEPseOzC, qykyPjDAzNgtLsEPYTsNrJaNK
[EX A]: DAzNgtLsEP

[EX Q]: XjlTExehPOZ, sOzTExeUzIC
[EX A]:
TExe