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

Ex Input:
rEHxRBOktYreNkK, NCOktYreFFCFwi

Ex Output:
OktYre


Ex Input:
kWTQrtCaoTbXIiXDphMG, pLhxkfeDoTbXIiXDpCCzTYyZv

Ex Output:
oTbXIiXDp


Ex Input:
XCOajFbP, CQajFjlT

Ex Output:

ajF