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

[Q]: jeQzwP, kSQzxq
[A]: Qz


[Q]: sHndIbPaygfNvnquxIHeteW, huLmJWXZIgfNvnquxIViQDhbuoL
[A]: gfNvnquxI


[Q]: QaazBItbuNGRbTQamgPZLq, GgaECHfDBItbuNGRbTHQMXfH
[A]:
BItbuNGRbT