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

Ex Input:
cKsJcqYvZO, UrsJcqBC

Ex Output:
sJcq


Ex Input:
cvRdSsuNwGVEwSSrowDpaOu, gFMcLKIeLwNwGVEwSSroUGskaoloqC

Ex Output:
NwGVEwSSro


Ex Input:
kyADtWLlnmYv, tcaKvDtWLlnvBq

Ex Output:

DtWLln