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

[Q]: UtUSmsOI, dCUSmGoQ
[A]: USm


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


[Q]: SIIPePlrkftKkzfgdjg, JqNnXHrkftKkzOMUwmc
[A]:
rkftKkz