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

Ex Input:
NwmTIZSnlKGG, qAYIZSnfWRd

Ex Output:
IZSn


Ex Input:
sRTQgRgRUjEooapKdR, vzsBgRUjEooLBkYeH

Ex Output:
gRUjEoo


Ex Input:
dQVUcGizzzaE, aQwiSVUcGiiOh

Ex Output:

VUcGi