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

pySBCdpe, AEBCdOR
BCd

jAinxmaQUrmu, jqeEnxmaQUrWlrEqW
nxmaQUr

dGcJtRihkopcSYQndYmSab, BTjxoDpkopcSYQnYDAzk

kopcSYQn