\documentclass[a4paper]{article}
\usepackage{pdfpages}

\newcount\stran
\input ../stran.tex
%%% \advance\stran by -1
\divide\stran by 2

\begin{document}
\newcount\citac
\citac=0
\includepdfset{landscape}

\loop
\advance\citac by 1
\ifodd\citac
  \includepdf[pages={\the\citac},angle=270]{ib-temp-b}
    \else
  \includepdf[pages={\the\citac},angle=90]{ib-temp-b}
\fi

\ifnum\citac<\stran\repeat

\end{document}
