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

sGrHRmELarByxp, cDCUnmELarBXbEfM
mELarB

OVVkkdeHoFlyNROyCP, zFVUJbvkkdeHoFlysF
kkdeHoFly

mOGzbnDXWnNurkBXtcqZ, NLahGzbnDXWnNYgMTOR

GzbnDXWnN