\documentclass[12pt]{article}
\usepackage{amsthm,amsmath,amssymb}
\usepackage[utf8]{inputenc}



\def\N{\mathbb{N}}
\def\R{\mathbb{R}}
\def\Q{\mathbb{Q}}
\def\Z{\mathbb{Z}}
\def\C{\mathbb{C}}

\newcommand{\header}{\begin{center}
{\LARGE\sc $58$\textsuperscript{\rm{th}}\, International Symposium \\[2mm] on Functional Equations}\\[2mm]
{\large\bf Grillhof, Innsbruck, Austria, June 19--26, 2022}
\end{center}\vspace{-3mm}\hrule\vspace{3mm}}

\newcommand{\abst}[6]{%\newpage
\setcounter{equation}{0}
\header\vspace{1cm}\begin{center}
{\LARGE\bf #5}\\[4mm]{\Large\sc #2 #1}\\[1mm]{\large #3,  #4}\\[2mm]
\end{center}\vspace{7mm}\noindent #6}




\begin{document}

\abst{Surname}%
{Given name(s)}%
{Affiliation}%
{Country}%
{Title}%
{
Text of the abstract of at most 10 lines (including references).
}

\end{document}
