% !TeX program = xelatex
\documentclass[a5paper, twoside]{article}

\usepackage{xeCJK}
\usepackage{adjustbox}
\usepackage{graphicx}
\usepackage{tabu}
\usepackage{longtable}
\usepackage{makecell}
\usepackage[bindingoffset=0.5in]{geometry}

\setCJKmainfont{Noto Sans CJK JP}

\begin{document}
  \renewcommand{\arraystretch}{2}
    \input{tex/n5.tex}
    \newline{}
    \input{tex/n4.tex}
    \newline{}
    \input{tex/n3.tex}
    \newline{}
    \input{tex/n2.tex}
    \newline{}
    \input{tex/n1.tex}
\end{document}