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

[Q]: ykDpbd, YFDpmO
[A]: Dp


[Q]: jFVaEHbMrrkW, ekfVaEHbPnBnM
[A]: VaEHb


[Q]: FRtvCg, AKtvoC
[A]:
tv