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

[Q]: yiKkIxbKvNk, znaIxbKggg
[A]: IxbK


[Q]: sRTQgRgRUjEooapKdR, vzsBgRUjEooLBkYeH
[A]: gRUjEoo


[Q]: psblwfTGoxjZP, lWQxlwfTGowRJ
[A]:
lwfTGo