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

Ex Input:
GlAYDsKQoXy, IxDsKQuK

Ex Output:
DsKQ


Ex Input:
YCAyruPTTHWhCYaiXfIl, OETdzqAyruPTTHWgS

Ex Output:
AyruPTTHW


Ex Input:
rgPRVLKrTe, mGxRRVLKgkX

Ex Output:

RVLK