edge away from the start vertex (0) before visiting those two edges away.</p>
         <h2>Shortest paths<a name="13"></a></h2>
         <p>In the previous two examples, the distance between vertices was equivalent to the number of edges.  Some graphs, however,
            have specific weights, such as the graph of flights between airports.  We can use this information to build information about
            the <i>shortest path</i> between two nodes in a network.
         </p><pre class="codeinput"><span c