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

[EX Q]: egYXVtCPvWxP, VMOolyVtCPvWjIx
[EX A]: VtCPvW

[EX Q]: OYERnjubLFovtcS, FngzQJVGERnjubLFafmzq
[EX A]: ERnjubLF

[EX Q]: IzzyoviDyif, DNCyoviHjZ
[EX A]:
yovi