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

Answer: QHJ


Question: spUbdWDLWCeqr, vIuHkWDLWCQEPaz

Answer: WDLWC


Question: vujACgAOrRFJJM, bEjACgAOkvY

Answer:
jACgAO