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]: ykDpbd, YFDpmO
[A]: Dp


[Q]: NLWRXfzWyU, DVhWRXfeeE
[A]:
WRXf