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

[Q]: QzJdafaGRLWEguLkOaw, brmPLBoaGRLWEguEaF
[A]: aGRLWEgu


[Q]: PivhPfah, XSghPfOi
[A]: hPf


[Q]: sFFxpRNY, HTFxpRrI
[A]:
FxpR