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

[Q]: VRamNL, mUamIB
[A]: am


[Q]: LiiFMMLGfNHVnnga, beXMMLGfNHVsjdfdN
[A]: MMLGfNHV


[Q]: ggQRBBWrvtdRhtq, eyxLaBWrvtPgoCs
[A]:
BWrvt