HELP FOR 60 POINTS!
Function $C$ is defined on positive integers as follows:
\[C(n) = \begin{cases}
\dfrac n 2 & \text{if $n$ is even}, \\
3n+1 & \text{if $n$ is odd}.
\end{cases}\]Find all $n$ such that $C^{3}(n) = 16$.

If you find more than one, then list the values separated by commas.