\documentclass{article}
\usepackage[x11names, rgb]{xcolor}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{snakes,arrows,shapes}
\usepackage{amsmath}

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\usepackage{xepersian}
\settextfont[Scale=1]{XBNiloofar}
\setdigitfont{PGaramond}
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\begin{document}
\pagestyle{empty}
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\enlargethispage{100cm}
% Start of code
% \begin{tikzpicture}[anchor=mid,>=latex',line join=bevel,]
\begin{tikzpicture}[>=latex',line join=bevel,]
  \pgfsetlinewidth{1bp}
%%
\pgfsetcolor{black}
  % Edge: a_2 -> a_3
  \draw [->] (43.74bp,77.457bp) .. controls (57.166bp,66.596bp) and (76.204bp,51.194bp)  .. (99.335bp,32.482bp);
  % Edge: a_1 -> a_5
  \draw [->] (99bp,161.6bp) .. controls (99bp,149.75bp) and (99bp,133.82bp)  .. (99bp,110.08bp);
  % Edge: a_3 -> a_1
  \draw [->] (123.9bp,35.517bp) .. controls (131.62bp,53.809bp) and (141.34bp,84.136bp)  .. (135bp,110bp) .. controls (131.12bp,125.84bp) and (122.89bp,142.08bp)  .. (109.92bp,163.43bp);
  % Edge: a_1 -> a_2
  \draw [->] (86.459bp,164.02bp) .. controls (75.376bp,150.78bp) and (59.041bp,131.27bp)  .. (39.639bp,108.1bp);
  \definecolor{strokecol}{rgb}{0.0,0.0,0.0};
  \pgfsetstrokecolor{strokecol}
  \draw (72bp,136bp) node {$x_1+x_3^2+z+c+v~~$};
  % Node: a_5
\begin{scope}
  \definecolor{strokecol}{rgb}{0.0,0.0,0.0};
  \pgfsetstrokecolor{strokecol}
  \draw (99bp,92bp) ellipse (27bp and 18bp);
  \draw (99bp,92bp) node {$a_5$};
\end{scope}
  % Node: a_3
\begin{scope}
  \definecolor{strokecol}{rgb}{0.0,0.0,0.0};
  \pgfsetstrokecolor{strokecol}
  \draw (116bp,18bp) ellipse (27bp and 18bp);
  \draw (116bp,18bp) node {$a_3$};
\end{scope}
  % Node: a_2
\begin{scope}
  \definecolor{strokecol}{rgb}{0.0,0.0,0.0};
  \pgfsetstrokecolor{strokecol}
  \draw (27bp,92bp) ellipse (27bp and 18bp);
  \draw (27bp,92bp) node {$a_2$};
\end{scope}
  % Node: a_1
\begin{scope}
  \definecolor{strokecol}{rgb}{0.0,0.0,0.0};
  \pgfsetstrokecolor{strokecol}
  \draw (99bp,180bp) ellipse (27bp and 18bp);
  \draw (99bp,180bp) node {$\frac{\gamma}{x^2}$};
\end{scope}
%
\end{tikzpicture}
% End of code
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\end{document}
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