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

[Q]: ARGchkRez, kUwchkZPE
[A]: chk


[Q]: dmigbcBoWdAIyaeE, zXiKQFbcBoWdAIyaEypIjJpwbU
[A]: bcBoWdAIya


[Q]: hVQyfOntBPj, rkJfOntBKmQ
[A]:
fOntB


