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

Ex Input:
esIMEOgV, tNIMEybb

Ex Output:
IME


Ex Input:
RtAchtNymcswVk, FWRuRchtNymcswUkoERHyML

Ex Output:
chtNymcsw


Ex Input:
bdGXndJGWyaRQ, ABptONXndJGWyOGYqrJ

Ex Output:

XndJGWy