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

mXHhaCEIwqwEZcz, JZPXbYHhaCEIwZmna
HhaCEIw

SFQHJlK, dHfQHJoUC
QHJ

WrCOfn, gUCOMx

CO