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\begin{document}
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\centerline{\large \bf Title of the Abstract}
\centerline{\large \bf Title to be Continued Here if Too Long}
\bigskip

\centerline{Author 1}
\centerline{\it Institution Name, Country}
\centerline{e-mail (Author 1)}
\smallskip

\centerline{Author 2\thanks{
presented by Author 2}}
\centerline{\it Institution Name, Country}
\centerline{e-mail (Author 2)}

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\par

% Text of the abstract (100-200 words).

\bigskip

{\bf 1 Presented by Author 2}
% May be presented by Author1, Author2, or Author3

\end{document}