Let $f$ be defined by

Let $f$ be defined by 

\[f(x) = \left\{
\begin{array}{cl}
2-x & \text{ if } x \leq 1, \\
2x-x^2 & \text{ if } x>1.
\end{array}
\right.\]

Calculate $f^{-1}(-3)+f^{-1}(0)+f^{-1}(3)$.