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

Ex Input:
ICizmXnKMpUH, oDrnmXnKgWXX

Ex Output:
mXnK


Ex Input:
CzkPtkpMTDeNZwCPbJJn, HzpMVDeNZwCPbJVOU

Ex Output:
DeNZwCPbJ


Ex Input:
kPdfcPuc, RSZdfczW

Ex Output:

dfc