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

[EX Q]: cxYVucnmEQopeWHrPJ, jNnOaYVucnmEQoSE
[EX A]: YVucnmEQo

[EX Q]: XYnCjAWPHHJ, gmCjAWPHpmwVsm
[EX A]: CjAWPH

[EX Q]: MWKkAg, ymKkOa
[EX A]:
Kk