If $f : \mathbb{R} \to \mathbb{R}$ and $g : \mathbb{R} \to \mathbb{R}$ are defined by $f(x) = |x|$ and $g(x) = [x - 3]$ for $x \in \mathbb{R}$, then $\{g(f(x)) : -\frac{8}{5} < x < \frac{8}{5}\}$ is equal to