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\documentclass[a4paper,11pt,chapter]{report}

\usepackage[hangul]{kotex}

\author{저자}

\title{제목}

\begin{document}

\maketitle

\renewcommand{\contentsname}{목차}

\tableofcontents

\chapter{챕챕}

\section{헥헥}

\subsection{}

\section{Good Bye World}

\end{document}