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

Ex Input:
KKrCLvJKRoyV, WDeLvJKCBdS

Ex Output:
LvJK


Ex Input:
ezVsFayUPcrte, lfsFayUMPTqx

Ex Output:
sFayU


Ex Input:
CvEzeaarsnBUfBCeXiNoVVvv, UFSBqsnBUfBCeXiWKMtlQeThZ

Ex Output:

snBUfBCeXi