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

XmiLktrUjJDOCJ, UIKrUjJDOQsR
rUjJDO

CMrTXnTnTVaR, srnXnTnTDNULO
XnTnT

ALIvkPOfnT, jMvkPOfpiopx
vkPOf