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

Ex Input:
bmsrkXGb, GcarkXOZF

Ex Output:
rkX


Ex Input:
sUdaWtsiRgqAYHykrHwjyDvZgD, MJdFXYiRgqAYHykrakSGHMr

Ex Output:
iRgqAYHykr


Ex Input:
FldsHWdcKBIbaeYHZVjX, DngPTBIbaeYHZVNMLsFzy

Ex Output:

BIbaeYHZV