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

[Q]: ZyrpGdXvvtrKQIxU, CLNGdXvvtrKQDpicfqLdt
[A]: GdXvvtrKQ


[Q]: BrDGrTD, PBHDGrDw
[A]: DGr


[Q]: ilRazqmPvrHdSvd, OvqmPvrHdSHKNRkBRM
[A]:
qmPvrHdS