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

Ex Input:
kUoqCMPFTqGE, guoqCMPkwJs

Ex Output:
oqCMP


Ex Input:
YWNPkA, LuNPnN

Ex Output:
NP


Ex Input:
tQdCVbYREOxKaNeod, fgEEUeREOxKaNJqNXFfK

Ex Output:

REOxKaN