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

[Q]: VutZiVkDQcVpQO, BDQVDyBdiVkDQcVpuvNN
[A]: iVkDQcVp


[Q]: fREVIdeTcakgFnwDWTVev, IbtXImseeTcakgFnwDYsKBAlux
[A]: eTcakgFnwD


[Q]: LkynLh, Kwynvk
[A]:
yn