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

Ex Input:
CiTNsbepy, DFNsbeZl

Ex Output:
Nsbe


Ex Input:
pySBCdpe, AEBCdOR

Ex Output:
BCd


Ex Input:
UldKHMpUYADGfEUGcSon, nPHMpUYADGfEKqHCLPmL

Ex Output:

HMpUYADGfE