instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
YHLJZrFQ, aSLJZQuo
answer:
LJZ


question:
jJjsASFfCqVV, AkjsASFfBFwPy
answer:
jsASFf


question:
zNOTtdpxYnndrSXdNVwd, LKeQVExYnndrSXdNAdpZQh
answer:

xYnndrSXdN