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

skZGHS, HsZGge
ZG

fWJdaAfOCfejXZvidHM, gOpfOCfejXZbtLvSLZI
fOCfejXZ

uqazNuZhdJhw, KbnrzNuZhBdp

zNuZh