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

Ex Input:
hUpEbyvEcQ, dHpEbyvEvwsXcN

Ex Output:
pEbyvE


Ex Input:
gTjTwC, OUjTgM

Ex Output:
jT


Ex Input:
zKykjG, AmykRN

Ex Output:

yk