instruction:
In this task, you are given two strings A, B. Find the longest common substring in the strings A and B.
question:
VpJvIZdkzKovjc, BZEizZdkzKYZ
answer:
ZdkzK


question:
hUpEbyvEcQ, dHpEbyvEvwsXcN
answer:
pEbyvE


question:
yoWMQbupEkIwJrRcG, gCsNyqbupEkIgvot
answer:

bupEkI