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

[EX Q]: FCKbAgSVgj, wAEAWbAgSVSVwD
[EX A]: bAgSV

[EX Q]: IVnbnqBqdPcXfHotUzCYoaGQy, PAlyypBRRBqdPcXfHotpZs
[EX A]: BqdPcXfHot

[EX Q]: NvjXeV, WnjXio
[EX A]:
jX