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

Ex Input:
uqDaPS, XyDaMZ

Ex Output:
Da


Ex Input:
xtCJGe, DXCJSw

Ex Output:
CJ


Ex Input:
YpronEMqkNBSqt, pHronEMqkaHDH

Ex Output:

ronEMqk