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: nYoRQU, gQoRZQ

Answer: oR


Question: OrcQOvMBhmwP, mnWrzcQOvMBnLwI

Answer: cQOvMB


Question: RcONLFCvJ, tXUNLFis

Answer:
NLF