{
my %r2d;
@r2d{qw(
  i ii iii iv v vi vii viii ix
  x xx xxx xl l lx lxx lxxx xc
  c cc ccc cd d dc dcc dccc cm
  m mm mmm
  )} = map { my $n = $_; map $n * $_, 1 .. 9 } 1, 10, 100, 1000;
use List::Util qw( sum );
sub roman_to_dec3
  {
  sum @r2d{ (lc shift) =~ /
    ix|iv|iii|ii|i|
    viii|vii|vi|v|
    xxx|xx|xl|xc|x|
    lxxx|lxx|lx|l|
    cm|cd|ccc|cc|c|
    dccc|dcc|dc|d|
    mmm|mm|m|
    ./gx }
  }
}