\begin{pseudo}*

    \hd{Backward}(V, E, v, i) \\

    $v.\id{label} = i$ \\

    for $(u,v)\in E$ \\+
        if $0 < v.\id{label} < i$ \\+
            \pr{Backward}(V, E, u, i) \\--

    for $(u,v)\in E$ \\+
        if $u.\id{label} \== 0$ \\+
            \pr{Backward}(V, E, u, i+1)

\end{pseudo}
