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

Ex Input:
XYnCjAWPHHJ, gmCjAWPHpmwVsm

Ex Output:
CjAWPH


Ex Input:
jXqEDHTCxTiUAICWZJdpmYq, GBTCxTiUAICZKnLgZBXi

Ex Output:
TCxTiUAIC


Ex Input:
aZVAusZMvhz, IjkXusZMllic

Ex Output:

usZM