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

QeNePjbLBKbDOuAVTJtXL, xjPVOyPbLBKbDOuDsMSEF
bLBKbDOu

sUdaWtsiRgqAYHykrHwjyDvZgD, MJdFXYiRgqAYHykrakSGHMr
iRgqAYHykr

SGjZzZUUqEtl, oYvqjZzZULave

jZzZU