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

pJqqIW, Ivqqxw
qq

KTAFonizDqCVvucpJWrItdw, rfFonizDqCVvYbGhb
FonizDqCVv

PKjEWRCLxVPsYRh, EaWRCLxVPsrGAG

WRCLxVPs