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

Ex Input:
YCAyruPTTHWhCYaiXfIl, OETdzqAyruPTTHWgS

Ex Output:
AyruPTTHW


Ex Input:
FCKbAgSVgj, wAEAWbAgSVSVwD

Ex Output:
bAgSV


Ex Input:
IKrQfT, crrQRg

Ex Output:

rQ