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

Ex Input:
PzXzvmYrlGZgOBk, iKnzvmYrlGZgOrs

Ex Output:
zvmYrlGZgO


Ex Input:
koddLvYmRXDUuUnW, GnqDYGmmRXDUuUquAnf

Ex Output:
mRXDUuU


Ex Input:
kKJWHs, fRJWCP

Ex Output:

JW