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

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


[Q]: VXSNlHzkB, EoNlHCiL
[A]: NlH


[Q]: znWaJypjzLzjcLheqAK, ZtHJypjzLzjmvEEkP
[A]:
JypjzLzj


