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

Ex Input:
iYSNsY, HSSNhP

Ex Output:
SN


Ex Input:
kWnjCoVmCSVuW, RILPKCoVmCSVbaOza

Ex Output:
CoVmCSV


Ex Input:
qHgsQGGrOKKN, ZvmQGGrOKxmlnIR

Ex Output:

QGGrOK