\documentclass{article}
\usepackage[utf8]{inputenc}
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% fails with "Command \k unavailable in encoding OT1".
\usepackage[T1]{fontenc}
\usepackage{polski}
\usepackage{amsmath}
\usepackage{relsize,amsfonts}
\usepackage{enumitem}
\usepackage{graphicx}
\usepackage{float}

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\title{Wspomaganie Decyzji w Warunkach Ryzyka\\ Projekt numer 25406\\}
\author{Krzysztof Rudnicki\\ numer albumu: 307585}
\date{\today}

\begin{document}

\maketitle

\tableofcontents
\newpage

	\input{sections/01-tresc-zadania}
	\input{sections/02-polecenia}
	\input{sections/03-wstep-teoretyczny}
	\input{sections/04-model-dwukryterialny-zysku-i-ryzyka}
\end{document}