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

Ex Input:
jLbHvZmecfxMcGLXGVsO, erFBGmecfxMcJtDyKGZ

Ex Output:
mecfxMc


Ex Input:
JzbEpAquDJFKcNvEWZxVqRV, PFiJlpAquDJFKcNcqOpMeAv

Ex Output:
pAquDJFKcN


Ex Input:
gDrlDrijNJRCVCrICRBBLPTKMHNW, NtTlRCVCrICRBBWGpPoBDc

Ex Output:

RCVCrICRBB