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: GBTHKtWUzK, ovVNKtWUmVJF

Answer: KtWU


Question: elloYaejTczBiiNOU, XoCPzloYaejTcXYtKODL

Answer: loYaejTc


Question: cucsqU, RUcsKU

Answer:
cs