Conversion Center

Roman numerals are based on seven symbols: "I" (one), "V" (five), "X" (ten), "L" (fifty), "C" (one hundred), "D" (five hunderd), "M" (one thousand). Number zero did not have its own Roman numeral, but a primitive form (nulla).
Conversion center uses a function which supports all seven Roman symbols. Romans used only capital (upper case) letters, so the inserted numeral should be wtitten with the same way. This function supports natural numbers from 1 upto 9,999,999.