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

EyvnjbVLF, vqnjblzR
njb

DQBpdnwVDcnCDEWpD, gAtCdnwVDcnCYv
dnwVDcnC

WkbKVuGX, tmqbKVXye

bKV