enter:
  i word   to insert word
  f word   to find word
  p        to print all
  x        to exit
> i the
the inserted
> i quick
quick inserted
> i brown
brown inserted
> i fox
fox inserted
> i jumped
jumped inserted
> i over
over inserted
> i the 
the inserted
> i lazy
lazy inserted
> i dogs
dogs inserted
> p
            /brown
                        /dogs
                   \fox
                        \jumped
                                      /lazy
                                \over
     /quick
            \the
=the