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

cKsJcqYvZO, UrsJcqBC
sJcq

gfXPLNzsyfEotmHL, oJeXPLNzsyJuXP
XPLNzsy

ZBabYWHZvgdHJngvEGesNWQ, CjJETvgdHJngvEmZsFHqCLA

vgdHJngvE