The Roman value is equivalent to: MDCCCCLXXXXIIII. While this is less compact, we shall see that this equivalent form without any subtractives can be useful.
By the way, not every source agrees to some of the details of Roman Numerals. As an example, we could expand the definition of a subtractive and form 99 as IC rather than XCIX as we would according to the rules above. Indeed, it is not clear if the Romans actually used the subtractives to write the numbers compactly.