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:
bUHPpvVtFQNSpUdg, zggEFoKBHPpvVtFQNHXsc

Ex Output:
HPpvVtFQN


Ex Input:
wjhoMCMvHXdErunpQuq, ZGQNcMvHXdErwClZbNI

Ex Output:

MvHXdEr