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

Ex Input:
oKZCAErEMqzODnkcNqxVdoBOC, yHzRJuSqzODnkcNqxExr

Ex Output:
qzODnkcNqx


Ex Input:
kIBDjQLEZepVNHqnKqhine, hTZepVNHqnYTajyzv

Ex Output:
ZepVNHqn


Ex Input:
lLXyIHBzV, lxjXyIHehm

Ex Output:

XyIH