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

[Q]: ljwjMioOwfOltGBaE, TneNGsoOwfOlxnWWW
[A]: oOwfOl

[Q]: RtOkkgLvhgfGlX, vCOkgLvhzOa
[A]: kgLvh

[Q]: QXZwldfcQ, JhXLZwldKa
[A]:
Zwld