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

[EX Q]: DnAzbgMtdPKsNCMpBfc, QdfXRkWREzbgMtdPKsGx
[EX A]: zbgMtdPKs

[EX Q]: BTvLVMYp, mjOvLVMqYo
[EX A]: vLVM

[EX Q]: UXuWekDNgsbBzXTkc, ZfJGDNgsbBzXnKBgVDhl
[EX A]:
DNgsbBzX