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

Q: jLbHvZmecfxMcGLXGVsO, erFBGmecfxMcJtDyKGZ

A: mecfxMc
****
Q: ezVsFayUPcrte, lfsFayUMPTqx

A: sFayU
****
Q: OVHBnseEzZ, fLnseEbDG

A:
nseE
****