{
  my %seen;
  sub track {
	my @path=@_;
	my $last=$path[-1];
	$seen{$last}=1;
 
	for my $next ( @{$graph{$last}} ) {
	  next if $seen{$next};
 
	  if ($next eq $stop) {
		print join ("->",@path,$stop),"\n";
	  } else {
		track(@path,$next);
	  }  
	}
	delete $seen{$last};
  }
}