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

[Q]: cvZfWOwa, xOfWOhZs
[A]: fWO


[Q]: EPUxsZtt, KgxsZuXM
[A]: xsZ


[Q]: izggdECiWFmCuOIn, fYWUdHCiWFmCuwfKi
[A]:
CiWFmCu