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

Ex Input:
fdxgzAMP, xrcxgzYW

Ex Output:
xgz


Ex Input:
PGjDRPDzGaBR, rpIJRPDzWi

Ex Output:
RPDz


Ex Input:
wDPzdubaVg, IqDzdubcJd

Ex Output:

zdub