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

[Q]: HKCoXQsLRtowYJ, PGRzNUQsLRtoLcqkn
[A]: QsLRto


[Q]: iYuUgULgqcAgd, kRNUgULgqFv
[A]: UgULgq


[Q]: tSMNbIWzDiLyFaKg, hoGcvbIWzDiLyzvwRm
[A]:
bIWzDiLy


