Let f:R→ R be a function defined as

f(x)= {3(1-IxI/2)i f IxI ≤ 2
{0i f IxI>2

Let g : R → R be given by g(x) = ƒ(x + 2) – ƒ(x – 2). If n and m denote the number of points in R where g is not continuous and not differentiable, respectively, then n + m is equal to _______.