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

Ex Input:
UZbmGVDzIaf, qfHwqGVDzIsd

Ex Output:
GVDzI


Ex Input:
LiiFMMLGfNHVnnga, beXMMLGfNHVsjdfdN

Ex Output:
MMLGfNHV


Ex Input:
mQvintdwLUpClREgxv, rYnoXBtdwLUpClRwxsqX

Ex Output:

tdwLUpClR