Set Operations: Venn Diagrams

The code that generates the previous PDF diagram:

\documentclass{standalone}
 
% Imported packages:
\usepackage{venndiagram} % Needed for drawing Venn diagrams

\begin{document}
\begin{venndiagram3sets}[labelNotABC={$U$}]
\fillA \fillB \fillC
\end{venndiagram3sets}%
\end{document}