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:
jyJrDIhxJtWbnooEXZ, uyXifNCIhxJtWbnVCUrt

Ex Output:
IhxJtWbn


Ex Input:
SViVUJrVDTi, VmZVUJrXDm

Ex Output:

VUJr


