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

Q: vSFxjd, AHFxpi

A: Fx
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Q: aiqZheFuLtXAGRCGNBTAX, ssnVdztXAGRCGNBTIqmSJLZcy

A: tXAGRCGNBT
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Q: kYDXtDBdtNAY, wXglDXtDBdtNdXlkRO

A:
DXtDBdtN
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