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

JAfPtjqqUYMD, cpXItjqqFN
tjqq

UtUSmsOI, dCUSmGoQ
USm

pxOwaZyULEHjUfKs, UKGmwaZyULEHjUycdLdgfieU

waZyULEHjU