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

[Q]: wYhGWdRC, cFGWdHEy
[A]: GWd


[Q]: EyvnjbVLF, vqnjblzR
[A]: njb


[Q]: EhHfWayPtguwPkGIY, xNyPtguwPzEuNir
[A]:
yPtguwP