Algorithm to convert Arabic integer into Roman numerals

Only need to convert from 1 to 399 max.

I have if N = 399, V = 5, X = 10, L = 50, C= 100

IF N >= 100 then

N/C = Quotient , Remainder

Print 'C' * Quotient

Set N = remainder

IF N>=50 then

N/L = Quotient , Remainder

Print 'L' * Quotient

Set N = remainder

I don't think this is correct since 399 = CCCXCIX. How do I do the above correctly?