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

Ex Input:
wrVsKN, mOVsWo

Ex Output:
Vs


Ex Input:
HSsyZzZLZAAq, MFEZzZLJC

Ex Output:
ZzZL


Ex Input:
egYXVtCPvWxP, VMOolyVtCPvWjIx

Ex Output:

VtCPvW