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

Ex Input:
oWwqraAz, uxTqraonu

Ex Output:
qra


Ex Input:
biAihydBoNlzR, IAloNhydBolwUz

Ex Output:
hydBo


Ex Input:
QhBnGyhtCZQLzvEdTxjoSRzq, TNtUhyhtCZQLzvEKFVKmy

Ex Output:

yhtCZQLzvE