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

Ex Input:
zqwhMdAdXQfQCAmVNaYZm, toYMIwQeadAdXQfQCAmLyheFOv

Ex Output:
dAdXQfQCAm


Ex Input:
mvIvSzMtYsfVLdaGEmef, wnzMtYsfVLdaKm

Ex Output:
zMtYsfVLda


Ex Input:
jgbXnQnrRF, GGjbXnQnUGu

Ex Output:

bXnQn