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

[EX Q]: zzEhnt, sYEhtc
[EX A]: Eh

[EX Q]: tGBRASi, QABRAtL
[EX A]: BRA

[EX Q]: WrkoFiNOaghTdocfWLW, jdiNOaghTfewH
[EX A]:
iNOaghT