LaTeX.org

I have a top level source file.
\documentclass{beamer}

\begin{document}
\frame{one}
\input{t2}
\end{document}
It includes (input) another file "t2.tex" with this content.
\frame{two}
When I execute "pdflatex t.tex" I get a PDF with three slides (an additional empty slide in between).

Any ...