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

Ex Input:
YXsgPE, ENsgSO

Ex Output:
sg


Ex Input:
JKZiYILNeNQbJyznES, PHKILNeNQbJylltYH

Ex Output:
ILNeNQbJy


Ex Input:
vWukKztHSSTkl, IcPIztHSSnXHM

Ex Output:

ztHSS