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

Ex Input:
HKqfdEvqDuGhWByFlzIEeYh, VVaZfkLCMuGhWByFlzIOZaXbMCA

Ex Output:
uGhWByFlzI


Ex Input:
gHFwDorPbNPORVgdLW, AfqDQvCGFwDorPbNPVPVmbQ

Ex Output:
FwDorPbNP


Ex Input:
EqCzhl, xvCzaR

Ex Output:

Cz