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

Q: EyvnjbVLF, vqnjblzR

A: njb
****
Q: eJPZzg, lFPZbI

A: PZ
****
Q: QRcQXcfPqAURTLKkBOrD, vQGPqAURTLkSeeeZk

A:
PqAURTL
****