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

[Q]: kWTQrtCaoTbXIiXDphMG, pLhxkfeDoTbXIiXDpCCzTYyZv
[A]: oTbXIiXDp


[Q]: XHqQIPw, brqQIkAt
[A]: qQI


[Q]: TzpmXHxoKY, ltrBXHxoXSS
[A]:
XHxo