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

feYKRk, PrYKMW
YK

KTAFonizDqCVvucpJWrItdw, rfFonizDqCVvYbGhb
FonizDqCVv

hGmOWNkOngMa, TXXWNkOndGZI

WNkOn