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

mXHhaCEIwqwEZcz, JZPXbYHhaCEIwZmna
HhaCEIw

qQkmYsYN, UhkmYHSy
kmY

KWYtMXtN, mNYtMVCy

YtM