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

Q: ChKUlYUTQQBjZMZkgEed, lmQQBjZMZkgdEf

A: QQBjZMZkg
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Q: EJZYVxgFxPoOSDlLfK, uTLTIETHZYVxgFxPoPwr

A: ZYVxgFxPo
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Q: PzXzvmYrlGZgOBk, iKnzvmYrlGZgOrs

A:
zvmYrlGZgO
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