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: xfZYYDKEqoRRu, ztCeYYDKEqoPG

Answer: YYDKEqo


Question: qczzCr, zDzzUI

Answer: zz


Question: GBRPhHbZZmzhqllWPmOZcuR, oBiyjzZZmzhqlleneuA

Answer:
ZZmzhqll