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

[Q]: hRVyvwHqnN, geHeyvwHqiBiYJ
[A]: yvwHq


[Q]: OBzHWjmkcgVGPyv, gCHWjmkcgVMq
[A]: HWjmkcgV


[Q]: wHnQDYtpOQ, xOinQDYtyBl
[A]:
nQDYt