sub atomize {
  my $string = shift;

  my @atoms = split / /, $string;

  # the most we are going to combine is word -1, word, and word +1.

  my @molecules;

  my $ofs = $";
  for ( my $i = 0; $i < $#atoms; $i++ ) {
    $" = '';
    my $molecule = "@atoms[$i-1,$i,$i+1]";
    push @molecules, $molecule;
  }

  $" = $ofs;
  return (\@atoms, \@molecules);
}

sub search_ms_nums {
  my @words = (@_);

  foreach my $word (@words) {
    return $word if is_ms_num( $word );
  }
  return undef;
}