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

XwBMFIV, SNLBMFZQ
BMF

vSFxjd, AHFxpi
Fx

DwGVrcqrWAzvUQCNgdmyE, eFcExmqrWAzvUQkisxub

qrWAzvUQ