using System;

​

namespace Romans_to_Arabic{

    public class Program4

    {

        public static void Main()

        {

            string input;

            Console.Write("Roman Numeral: ");

            input = Console.ReadLine().ToUpper();

​

            Console.Write("Arabic Conversion: ");

            Roman roman = new Roman();

            Console.WriteLine(roman.calculateRomanNumber(input));

        }

​

    }

​

    class Roman

    {

        public int calculateRomanNumber(string romanNumber)

        {

            int res = 0;

            for (int i = 0; i < romanNumber.Length; i++)

            {

                {

                    if (romanNumber[i].Equals('I'))

                    {

                        if (i == romanNumber.Length - 1)

                            ++res;

                        else if (romanNumber[i + 1].Equals('I'))

                            ++res;

                        else

                            --res;

                    }

                    if (romanNumber[i].Equals('V'))

                    {

                        if (i == romanNumber.Length - 1)

                            res += 5;

                        else if (romanNumber[i + 1].Equals('I') || romanNumber[i + 1].Equals('V'))

                            res += 5;

                        else

                            res -= 5;

                    }

                    if (romanNumber[i].Equals('X'))

                    {

                        if (i == romanNumber.Length - 1)

                            res += 10;

                        else if (romanNumber[i + 1].Equals('I') ||  romanNumber[i + 1].Equals('V') || romanNumber[i + 1].Equals('X'))

                            res += 10;

                        else

                            res -= 10;

                    }

                    if (romanNumber[i].Equals('L'))

                    {

                        if (i == romanNumber.Length - 1)

                            res += 50;

                        else if ( romanNumber[i + 1].Equals('I') || romanNumber[i + 1].Equals('V') || romanNumber[i + 1].Equals('X') ||romanNumber[i + 1].Equals('L'))

                            res += 50;

                        else

                            res -= 50;

                    }

                    if (romanNumber[i].Equals('C'))

                    {

                        if (i == romanNumber.Length - 1)

                            res += 100;

                        else if (romanNumber[i + 1].Equals('I') || romanNumber[i + 1].Equals('V') || romanNumber[i + 1].Equals('X') ||  romanNumber[i + 1].Equals('L') || romanNumber[i + 1].Equals('C'))

                            res += 100;

                        else

                            res -= 100;

                    }

                    if (romanNumber[i].Equals('D'))

                    {

                        if (i == romanNumber.Length - 1)

                            res += 500;

                        else if (romanNumber[i + 1].Equals('I') || romanNumber[i + 1].Equals('V') || romanNumber[i + 1].Equals('X') || romanNumber[i + 1].Equals('L') || romanNumber[i + 1].Equals('C') || romanNumber[i + 1].Equals('D'))

                            res += 500;

                        else

                            res -= 500;

                    }

                    if ( romanNumber[i].Equals('M'))

                    {

                        if (i == romanNumber.Length - 1)

                            res += 1000;

                        else if (romanNumber[i + 1].Equals('I') ||  romanNumber[i + 1].Equals('V') ||romanNumber[i + 1].Equals('X') || romanNumber[i + 1].Equals('L') || romanNumber[i + 1].Equals('C') || romanNumber[i + 1].Equals('D') || romanNumber[i + 1].Equals('M'))

                            res += 1000;

                        else

                            res -= 1000;

                    }

                }

            }

            return res;

        }

​

    }

}

​

​