/** An edge of a graph */

class Edge implements Comparable{
  int fst;
  int snd;
  
  Edge(int fst, int snd) {
    this.fst = fst;
    this.snd = snd;
  }

  public boolean lessThan(Comparable c) {
    Edge e = (Edge) c;
    return (fst < e.fst ||
	    fst == e.fst && ((snd > e.snd) ^ (fst < snd) ^ (fst < e.snd)));
    /* the funky second line with the XORs tests for the cyclic ordering
       snd < fst == e.fst < e.snd */
  }

}