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

Ex Input:
HqaOvLaZbs, RifOvLaZkh

Ex Output:
OvLaZ


Ex Input:
VpJvIZdkzKovjc, BZEizZdkzKYZ

Ex Output:
ZdkzK


Ex Input:
rxauwxWMMG, qOvauwxWsX

Ex Output:

auwxW