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

Ex Input:
OXdSmcKG, XbDdSmJl

Ex Output:
dSm


Ex Input:
jexvmCmveGzFUimQMx, RVwOSJveGzFUimrcOwjEwe

Ex Output:
veGzFUim


Ex Input:
ArfFgWwXmV, OrPZgWwXTvQq

Ex Output:

gWwX