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

[Q]: JqdTDnZqSuSVcMsx, TEtDDnZqSuZa
[A]: DnZqSu


[Q]: xtCJGe, DXCJSw
[A]: CJ


[Q]: IwdUnQvvvktK, LwnjUnQvvvPaZxv
[A]:
UnQvvv