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

yhhzISsXKEbA, KlPrazISsXKzmrVBG
zISsXK

PzXzvmYrlGZgOBk, iKnzvmYrlGZgOrs
zvmYrlGZgO

CtIZehzlWXOuTLjZ, KtNoEjhZehzlWXlq

ZehzlWX