[Tex/LaTex] Too many math alphabets in beamer

Question

This beamer attempt produces the error "Too many math alphabets used in version normal.". Using the article class produces no error as does removing either chemmacros or siunitx, but I need those packages.

\documentclass{beamer}

\usepackage{chemmacros}
\chemsetup{greek=fourier}

\usepackage{siunitx}
\usepackage{helvet, mathpazo}%suggested by siunitx


\begin{document}
\begin{frame}
\num{1+2i}
\end{frame}
\end{document}

Answer 1

Add \usefonttheme{professionalfonts}. Compiles for me, then.

\documentclass{beamer}
\usefonttheme{professionalfonts}
\usepackage{chemmacros}
\chemsetup{greek=fourier}

\usepackage{siunitx}
\usepackage{helvet, mathpazo}%suggested by siunitx


\begin{document}
\begin{frame}
\num{1+2i}
\end{frame}
\end{document}