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

[Q]: vhZuXCsIkQR, YflCuXCsIkLu
[A]: uXCsIk


[Q]: RwqzMTeLMdPx, qaWtYhqzMTeLMdHbWDT
[A]: qzMTeLMd


[Q]: zqWNBnNmBCqxfu, DYvBnNmBZJ
[A]:
BnNmB