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

Ex Input:
sRTQgRgRUjEooapKdR, vzsBgRUjEooLBkYeH

Ex Output:
gRUjEoo


Ex Input:
osmJJcZlDAXBgJFsJKa, rzPNlDAXBgJYrgXlH

Ex Output:
lDAXBgJ


Ex Input:
ZzzQrFdO, GDIHzQrFik

Ex Output:

zQrF


