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]: QeNePjbLBKbDOuAVTJtXL, xjPVOyPbLBKbDOuDsMSEF
[A]: bLBKbDOu


[Q]: oSQGDbNgqYExrHklorAvy, aMjGDbNgqYExwT
[A]:
GDbNgqYEx