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

Ex Input:
LudFxiaqbX, UWMPnFxiaqikiDx

Ex Output:
Fxiaq


Ex Input:
BVipiZoGXaWdjmDsxWP, yxppsiYkiZoGXaWdjoDRuKW

Ex Output:
iZoGXaWdj


Ex Input:
wFpIvdJShBh, uqofdvdJShIBu

Ex Output:

vdJSh