\documentclass{article}
\usepackage{argoclp}
\catcode`\_=\active
\def_{\_}

\def\d{{\fontencoding{T1}\selectfont\dj}}

\def\D{{\fontencoding{T1}\selectfont\DJ}}

\setlength{\textheight}{22cm} 
\newtheorem{axiom}{Aksioma}
\newtheorem{theorem}{Teorema}
\newcounter{proofstepnum} 

\begin{document}

\title{High school geometry theorems}
\author{Hilbert's axiomatic system.\\
Formalizovano od strane: Sana Stojanovic Djurdjevic \\
Dokaz generisan uz pomo\'{c}: ArgoGeoChecker.}
\date{30.03.2018.}
\maketitle

\begin{theorem}[th_8_01.]
Pod pretpostavkom da va\v{z}i $\neg col(A, B, C)$ i $bet(B, D, C)$ i $bet(C, E, A)$ i $bet(A, F, B)$ pokazati da va\v{z}i $\neg col(D, E, F)$.
\end{theorem}

\hrule 

\end{document}
