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: KTAFonizDqCVvucpJWrItdw, rfFonizDqCVvYbGhb

Answer: FonizDqCVv


Question: koIZvrJmfKCO, TBvrtjcWIZvrJmfKRZDOE

Answer: IZvrJmfK


Question: xrlWBBSnfBnRKMmz, AtJTGBSnfBngun

Answer:
BSnfBn