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

[Q]: QECPAHsg, bUfPAHOWb
[A]: PAH


[Q]: aWshKwEuYBBdSwIAyXw, wfVuYBBdSwIAseTxR
[A]: uYBBdSwIA


[Q]: lzUiUUjxMHSQvmb, GrMVOViUUjxMmQ
[A]:
iUUjxM