Мой код не будет компилироваться, где я ошибся?

Write a program that takes a decimal value between 1 and 10 and dis- plays its equivalent Roman numeral value. Display an error message if the value entered is outside of the acceptable range. Write a two class solution. The second class should allow the user to input a test value.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Pg322number1
{
    class Program
    {
        static void Main(string[] args)
        {
            int value;
            string roman;

            DisplayInstrution();
            value = GetDecimal();

            roman = CalculateRoman(value);

            DisplayResults(value, roman);
            Console.ReadKey();
        }


        public static void DisplayInstrution()
        {
            Console.WriteLine("This application allows decimal value between 1 and 10");
            Console.WriteLine("to be entered. It displays the equivalent roman numeral value.");
            Console.ReadKey();
        }

        public static int GetDecimal()
        {
            int value;
            Console.WriteLine("Decimal value: ");
            value = Int32.Parse(Console.ReadLine());

            return value;
        }

        public static string CalculateRoman(int value)
        {
            string result;

            if (value < 0 || value > 10)
                result = "Invalid input";
            else
                if (value == 1)
                result = "I";
            else
                if (value == 2)
                result = "II";
            else
                if (value == 3)
                result = "III";
            else
                if (value == 4)
                result = "IV";
            else
                if (value == 5)
                result = "V";
            else
                if (value == 6)
                result = "VI";
            else
                if (value == 7)
                result = "VII";
            else
                if (value == 8)
                result = "VIII";
            else
                if (value == 9)
                result = "IX";
            else
                result = "IX";

            return result;

        }

        public static void DisplayResults(int value, string roman)
        {
            if (value != 0)
            {
                Console.WriteLine("Roman value: " + roman);
            }
        }
    }
}