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

[Q]: PzXzvmYrlGZgOBk, iKnzvmYrlGZgOrs
[A]: zvmYrlGZgO


[Q]: AxAmDG, LTAmEV
[A]: Am


[Q]: kuKGln, fzKGUd
[A]:
KG