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

Ex Input:
ksRxEVrz, cOMRxEViwF

Ex Output:
RxEV


Ex Input:
wXGerDNhSNnCCedyzskswVnh, BfFNhSNnCCedybrUbI

Ex Output:
NhSNnCCedy


Ex Input:
SfVxJc, sdVxWL

Ex Output:

Vx