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

Ex Input:
DnAzbgMtdPKsNCMpBfc, QdfXRkWREzbgMtdPKsGx

Ex Output:
zbgMtdPKs


Ex Input:
dReySjyqecU, loSjyqiRl

Ex Output:
Sjyq


Ex Input:
HvgvzuWgCHJpbDSGwGyke, sRuJgCHJpbDhB

Ex Output:

gCHJpbD