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

Ex Input:
XjYkMfARxWBSBjuXyDrFt, EtUxIfiHkMfARxWBSckTLTTnR

Ex Output:
kMfARxWBS


Ex Input:
JAfPtjqqUYMD, cpXItjqqFN

Ex Output:
tjqq


Ex Input:
WabueClFMYyWTW, BIhTClFMYyDtYjoX

Ex Output:

ClFMYy