class Vertex {

  String id;
  Vertex next;
  Edge first;

  Vertex (String s, Vertex v, Edge e) {
     id = s;
     next = v;
     first = e;
  }

  Vertex (String s) {
     this (s, null, null);
  }

  @Override
  public String toString() {
     return id;
  }

class Edge {

  String id;
  Vertex target;
  Edge next;

  Edge (String s, Vertex v, Edge e) {
     id = s;
     target = v;
     next = e;
  }

  Edge (String s) {
     this (s, null, null);
  }

  @Override
  public String toString() {
     return id;
  }

}

class Graph {

  String id;
  Vertex first;

  Graph (String s, Vertex v) {
     id = s;
     first = v;
  }

  Graph (String s) {
     this (s, null);
  }

  @Override
  public String toString() {
     String nl = System.getProperty ("line.separator");
     StringBuffer sb = new StringBuffer (nl);
     sb.append (id + nl);
     Vertex v = first;
     while (v != null) {
        sb.append (v.toString() + " --> ");
        Edge e = v.first;
        while (e != null) {
           sb.append (e.toString());
           sb.append ("(" + v.toString() + "->"
              + e.target.toString() + ") ");
           e = e.next;
        }
        sb.append (nl);
        v = v.next;
     }
     return sb.toString();
  }

  public ArrayList<Edge> transitiveClosure(ArrayList<Vertex> v)
  {
      Graph g = new Graph("G+");
      ArrayList<Edge> edge = new ArrayList();
      Edge e = null;
      for(Vertex vertex : v)
      {
         System.out.print(vertex);
      }

          int next = 0;
          g.first = v.get(0);
          Vertex tmp = v.get(0);

         if(v.get(next) != null)
         {
            next++;
            tmp = v.get(next);
            e = new Edge(g.first.toString() + tmp);
            edge.add(e);
        //System.out.println(e);
         }
         if(v.get(next) !=null)
         {
             next++;
             tmp = v.get(next);
             e = new Edge(g.first.toString() + tmp);
             edge.add(e);
         }



      System.out.println("");
      return edge;

  }