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

Ex Input:
aIZIsqL, wxSZIsEnO

Ex Output:
ZIs


Ex Input:
gXwuhXJrEdzGOmLSKdK, TohXJrEdzGavU

Ex Output:
hXJrEdzG


Ex Input:
kTCKDGmirFtIOFZySRHiqIRRGe, hfOSuCksiFtIOFZySRHJHrssnlkiF

Ex Output:

FtIOFZySRH


