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

[Q]: wYhGWdRC, cFGWdHEy
[A]: GWd


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


[Q]: YHrKToLIiBjOkWNzgj, BohILIiBjOkvATKU
[A]:
LIiBjOk