\documentclass[a4paper,11pt]{article}
\usepackage[utf8]{inputenc}
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\usepackage[polish]{babel}
\usepackage{fourier}
\usepackage{geometry}

\geometry{width=126mm}


\begin{document}

\begin{tabular}{c|c|c}
\textbf{idmeczu} & \textbf{gospodarze} & \textbf{goscie} \\
\hline
1 & \{28, 23, 13, 12\} & \{26, 25, 25, 25\} \\
2 & \{25, 25, 25\}     & \{12, 17, 20\}     \\
3 & \{25, 25, 25\}     & \{10, 15, 17\}     \\
\end{tabular}

\end{document}
