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

Q: RNYHvcNnbsUdJLvS, PpNnbsUdglWhl

A: NnbsUd
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Q: lOedgdw, aoedgpn

A: edg
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Q: MLyzkExmhkJgXiFqJsGXamhgHG, xHoiwqcxmhkJgXiFqKOnQK

A:
xmhkJgXiFq
****