function RomanToDec(const Value: string): integer;
var
 i, lastValue, curValue: integer;
begin
 Result := 0;
 lastValue := 0;
 for i := Length(Value) downto 1 do
 begin
  case UpCase(Value[i]) of
  'C':
  curValue := 100;
  'D':
  curValue := 500;
  'I':
  curValue := 1;
  'L':
  curValue := 50;
  'M':
  curValue := 1000;
  'V':
  curValue := 5;
  'X':
  curValue := 10;
  else
  raise Exception.CreateFmt('Invalid character: %s', [Value[i]]);
  end;
  if curValue < lastValue then
  Dec(Result, curValue)
  else
  Inc(Result, curValue);
  lastValue := curValue;
 end;
end;