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

RMurrwPjlfG, QBKrrwPDkTM
rrwP

uGDJixAmSiVaFRmfKRM, NsTGxsJixAmSiVageSw
JixAmSiVa

CBAWdKhPWYnpxgQKb, AAtkCQhPWYnpjgLCb

hPWYnp