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

Q: oGaGjsaKsUpLQAg, iDGjsaKsUoYGuta

A: GjsaKsU
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Q: QvtDqzQiSknPbRCG, hVxHdqzQiSknPbumdpNIf

A: qzQiSknPb
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Q: gGqFjLwQPTiyfhn, hCLsPfqFjLwQPTBN

A:
qFjLwQPT
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