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

[EX Q]: nrIHKzJCdAQzUDRBYpg, JDzJCdAQzUMMYrLcfO
[EX A]: zJCdAQzU

[EX Q]: kIBDjQLEZepVNHqnKqhine, hTZepVNHqnYTajyzv
[EX A]: ZepVNHqn

[EX Q]: JZQZwECNILsJVOlAYDtetM, tRoNILsJVOlrX
[EX A]:
NILsJVOl