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

Ex Input:
HaLZdTX, tLLZdEXN

Ex Output:
LZd


Ex Input:
yhhzISsXKEbA, KlPrazISsXKzmrVBG

Ex Output:
zISsXK


Ex Input:
rzPCGCZ, CwEPCGqk

Ex Output:

PCG