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

cjDuPZOHjystHnF, okWVdUDuPZOHjSCaEecP
DuPZOHj

bOvlVNWf, iivlVzWt
vlV

vLHBkwSGVBBfMdFuWGjrJlqhs, YFyGVBBfMdFuWXZjw

GVBBfMdFuW