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

jFVaEHbMrrkW, ekfVaEHbPnBnM
VaEHb

RtAchtNymcswVk, FWRuRchtNymcswUkoERHyML
chtNymcsw

xKsWgwnTMCfBRiUHz, QhYLTzWwnTMCfBuOlmwI

wnTMCfB