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: bmsrkXGb, GcarkXOZF

Answer: rkX


Question: yrIDSuVuQU, UXTSuVuLcch

Answer: SuVu


Question: ywOYBLEN, qiTYBLaqd

Answer:
YBL