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

[Q]: HhBhJMpxpty, MxTJMpxnQEf
[A]: JMpx


[Q]: BICndZkjoSidWivWATvtqsS, FzVWjoSidWivFaQhkRT
[A]: joSidWiv


[Q]: PBRvsPFvmWVkPcfL, vqBEyFvmWVkPTDkZBms
[A]:
FvmWVkP