\documentclass[12pt]{article}
% comment
% the beginning of the header of the tex file.
% here we initialize the packages we need, the margins,
% format of the layout of the pages, the style etc.
\usepackage{amsmath}
\usepackage{amssymb}
\setlength{\oddsidemargin}{0.0cm}
\setlength{\evensidemargin}{0.0cm}
\setlength{\topmargin}{-10mm}
\advance\headheight by 2pt
\setlength{\footskip}{8mm}
\setlength{\textheight}{225mm}
\advance\textheight by-\headheight
\advance\textheight by-\headsep
\setlength{\textwidth}{165mm}
\def\baselinestrech{1.0}
\pagenumbering{arabic}
\pagestyle{headings}
% end of the header

% the document starts here
\begin{document}






\end{document}