\begin{tikzpicture}

\def\n {3}
\def\radius {2cm}

\foreach \i in {1,...,\n}
{
  \node[draw, circle] (v\i) at ({-360/\n * (\i+2)}:\radius) {$\i$};
}

  \draw[->] (v1) -- (v2);
  \draw[->] (v3) -- (v2);  
\end{tikzpicture}
