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: qMnjlfIsQRtUlPggCpHqu, gfVndMwYDIsQRtUlPgqBJKCX

Answer: IsQRtUlPg


Question: YlhtTQgHiffTbIbBrcHMqFKCdWz, HyregFgMffTbIbBrcHYUnnQvGlx

Answer: ffTbIbBrcH


Question: smcSykxCpWCmCiFz, YWykxCpWCDIesNJY

Answer:
ykxCpWC