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

Ex Input:
DhhYhrqVMXSoyvXQwqPKzWARAP, CaMXSoyvXQwqcDDtMsVqD

Ex Output:
MXSoyvXQwq


Ex Input:
edjRAatlaiCmWkpqMh, qDZYVWCDTRAatlaiCmYH

Ex Output:
RAatlaiCm


Ex Input:
hpUbCM, zZUbYl

Ex Output:

Ub