sub get_move_score {
  my @numbers = @_ or return("end", "", 0);
  return "shift", $numbers[0], $numbers[0] if 1 == @numbers;

  my $shift = shift @numbers;
  my $pop = pop @numbers;

  my $score_shift = $shift - (get_move_score(@numbers, $pop))[2];
  my $score_pop = $pop - (get_move_score($shift, @numbers))[2];

  if ($score_pop > $score_shift) {
    return "pop", $pop, $score_pop;
  }
  else {
    return "shift", $shift, $score_shift;
  }
}