use strict;
use warnings;

my %letters = ('I' => 1, 'V' => 5, 'X' => 10, 'L' => 50, 
               'C' => 100, 'D' => 500, 'M' => 1000);

my $roman = "MCCMLXXIV";  #1874

my $result = 0;
my $high_score = 0;

foreach my $letter ( split(//, reverse($roman)) ) {
  my $score = $letters{$letter};
  if ($score >= $high_score) {
    $result += $score;
  }
  else {
    $result -= $score;
  }

  $high_score = $score if $score > $high_score;
}
print "$result\n";