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

aWshKwEuYBBdSwIAyXw, wfVuYBBdSwIAseTxR
uYBBdSwIA

vhZuXCsIkQR, YflCuXCsIkLu
uXCsIk

VnCMbwS, LlxCMbqmX

CMb