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: cUCQXEFSgRZjK, RYdvUQXEFSgRZVlwx

Answer: QXEFSgRZ


Question: bUHPpvVtFQNSpUdg, zggEFoKBHPpvVtFQNHXsc

Answer: HPpvVtFQN


Question: RIxEUWcLmnMMSCGaLX, GwWgtsxEUWcLmnsGFeRJRn

Answer:
xEUWcLmn