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

[Q]: zgJGhxLU, EwJGhedW
[A]: JGh


[Q]: wYhGWdRC, cFGWdHEy
[A]: GWd


[Q]: UDigxDeuSla, HsCQgxDeudHHLx
[A]:
gxDeu