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

Ex Input:
IQIHqbEhpVuNATp, GIJIHqbEhpzWb

Ex Output:
IHqbEhp


Ex Input:
NUuLSmDjCKcJPc, lGGSLIDjCKcJBo

Ex Output:
DjCKcJ


Ex Input:
iYuUgULgqcAgd, kRNUgULgqFv

Ex Output:

UgULgq