Let \(f : \mathbb{R} \to \mathbb{R}\) be a function such that
\(f(f(x) + y) = f(x^2 - y) + 4f(x) y\)
for all real numbers \(x\) and \(y\)
Let \(n\) be the number of possible values of \(f(3)\), and let \(s\) be the sum of all possible values of \(f(3).\) Find \(n\times s.\)
