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

Ex Input:
YKpdeJQhzyYiPoODACUu, mjmnIlCehzyYiPoOzZ

Ex Output:
hzyYiPoO


Ex Input:
nXVXIEGP, fkXIEkU

Ex Output:
XIE


Ex Input:
DysYcTpMjBU, tvJYcTpMjyT

Ex Output:

YcTpMj