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

gfXPLNzsyfEotmHL, oJeXPLNzsyJuXP
XPLNzsy

OyrqfQQnzOFUzrkDM, iBkQQnzOFewhjvO
QQnzOF

WevyxScCnrmzQbDc, hXFkqNScCnrmOXkgQx

ScCnrm