Задача: Конвертер арабских чисел в римские

ConvertIntToRoman.cs

using System;
					
public class Program
{
	public static string ConvertIntToRoman(int n) 
	{
		if (n >= 1000) 
			return "M" + ConvertIntToRoman(n - 1000);

		if (n >= 500) 
			return n >= 900 ? ("CM" + ConvertIntToRoman(n - 900)) : ("D" + ConvertIntToRoman(n - 500));

		if (n >= 100) 
			return n >= 400 ? ("CD" + ConvertIntToRoman(n - 400)) : ("C" + ConvertIntToRoman(n - 100));

		if (n >= 50) 
			return n >= 90 ? ("XC" + ConvertIntToRoman(n - 90)) : ("L" + ConvertIntToRoman(n - 50));

		if (n >= 10) 
			return n >= 40 ? ("XL" + ConvertIntToRoman(n - 40)): ("X" + ConvertIntToRoman(n - 10));

		if (n >= 5) 
			return n == 9 ? "IX" : "V" + ConvertIntToRoman(n - 5);

		if (n > 0) 
			return n == 4 ? "IV" : "I" + ConvertIntToRoman(n - 1);

		return "";
	}
	
	public static void Main()
	{
		Console.WriteLine("UniLecs");
		
		// Tests
		Console.WriteLine("Answer = {0}", ConvertIntToRoman(3));    // III
		Console.WriteLine("Answer = {0}", ConvertIntToRoman(4));    // IV
		Console.WriteLine("Answer = {0}", ConvertIntToRoman(9));    // IX
		Console.WriteLine("Answer = {0}", ConvertIntToRoman(58));   // LVIII
		Console.WriteLine("Answer = {0}", ConvertIntToRoman(1994)); // MCMXCIV
	}
}