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

[Q]: lrBJDRkT, jmBJDrI
[A]: BJD


[Q]: WTnsmP, INnsIM
[A]: ns


[Q]: jwcBcoOsBLJKrjfugxb, IzTtZHoOsBLJKzbbnjR
[A]:
oOsBLJK