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

PzXzvmYrlGZgOBk, iKnzvmYrlGZgOrs
zvmYrlGZgO

aBlALASwuwTZmy, MdwASwuwIW
ASwuw

XWIzeRtthdaKwAxC, QMxIutthdaKoCQe

tthdaK