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

rszjOPpbXm, pnBujOPpWHz
jOPp

edjRAatlaiCmWkpqMh, qDZYVWCDTRAatlaiCmYH
RAatlaiCm

beOJMoPIdumpeaFeyhbRdB, BggJHIdumpeaFeqwRZZ

IdumpeaFe