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

Ex Input:
spUbdWDLWCeqr, vIuHkWDLWCQEPaz

Ex Output:
WDLWC


Ex Input:
OrcQOvMBhmwP, mnWrzcQOvMBnLwI

Ex Output:
cQOvMB


Ex Input:
bdCOjNchdKtvWzOI, FwejNchdKhEd

Ex Output:

jNchdK