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: XZslQqrShfCXRXyHrFVq, BtOQgQqrShfCXRRCRbMvXPM

Answer: QqrShfCXR


Question: kOrQWjLKnwN, xFsWjLKgr

Answer: WjLK


Question: WwYUJlld, uaYUJlXS

Answer:
YUJl