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

Ex Input:
sOSXbnluNuvwMETKda, JzXbnluNuvyeVHO

Ex Output:
XbnluNuv


Ex Input:
NNpkdhvgT, BMkAkdhvrwV

Ex Output:
kdhv


Ex Input:
jQejbKXbR, wOmjbKXFKeM

Ex Output:

jbKX