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

[EX Q]: VGRjWGHRcBdFmkVg, eSwqALQXWGHRcBdFsDXCM
[EX A]: WGHRcBdF

[EX Q]: IzwlZDJSEFPxfIud, xwWSYwlZDJSEFPbvSXTlS
[EX A]: wlZDJSEFP

[EX Q]: vOaowB, kuaoqp
[EX A]:
ao