In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.

[Q]: CiTNsbepy, DFNsbeZl
[A]: Nsbe


[Q]: PQSFjlnU, kTSFjMUh
[A]: SFj


[Q]: LdGFfgKQPOwefYePPdDqHg, WdMxKQPOwefYwxBV
[A]:
KQPOwefY