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

Ex Input:
NmtypJ, tQtyZD

Ex Output:
ty


Ex Input:
UldKHMpUYADGfEUGcSon, nPHMpUYADGfEKqHCLPmL

Ex Output:
HMpUYADGfE


Ex Input:
BVipiZoGXaWdjmDsxWP, yxppsiYkiZoGXaWdjoDRuKW

Ex Output:

iZoGXaWdj


