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

[Q]: lypuwWy, jRpuwcE
[A]: puw


[Q]: ugDpSMRvHM, DDwSMRvxw
[A]: SMRv


[Q]: IKfFFphPjQFCACVdnmuWAIVnsY, AkWUeRblFCACVdnmuWxHpGZCXwje
[A]:
FCACVdnmuW