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

Ex Input:
lQwpMQRxuVbJDv, UkzwpMQRxuDVT

Ex Output:
wpMQRxu


Ex Input:
xMxyohPBlJIEBqghiMdBQPwq, xsBlJIEBqghlMosK

Ex Output:
BlJIEBqgh


Ex Input:
QaazBItbuNGRbTQamgPZLq, GgaECHfDBItbuNGRbTHQMXfH

Ex Output:

BItbuNGRbT


