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

[Q]: spGRUmIYuGl, qkqRUmItqU
[A]: RUmI


[Q]: mXHhaCEIwqwEZcz, JZPXbYHhaCEIwZmna
[A]: HhaCEIw


[Q]: OlNkMfyTknRwqRJAkuKlHmB, vCeknRwqRJAkXMmuW
[A]:
knRwqRJAk


