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

Ex Input:
hCRsCCOoLMpjXwI, lVRCOoLMpxaYFbY

Ex Output:
COoLMp


Ex Input:
eJPZzg, lFPZbI

Ex Output:
PZ


Ex Input:
QGGxjYZubqcDnD, qMJvjYZubuLOwd

Ex Output:

jYZub