using System;

​

public class ToArabic {

    public virtual int RomanValue(char roman){

        if (roman == 'I' || roman == 'i')

            return 1;

        if (roman == 'V' || roman == 'v')

            return 5;

        if (roman == 'X' || roman == 'x')

            return 10;

        if (roman == 'L' || roman == 'l')

            return 50;

        if (roman == 'C' || roman == 'c')

            return 100;

        if (roman == 'D' || roman == 'd')

            return 500;

        if (roman == 'M' || roman == 'm')

            return 1000;

        return -1;

    }

    public virtual int ToDecimal(string str){

        int result = 0;

​

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

        {

            int s1 = RomanValue(str[i]);

            if (i + 1 < str.Length)

            {

                int s2 = RomanValue(str[i + 1]);

​

                if (s1 >= s2)

                {

                    result = result + s1;

                }

                else

                {

                   result = result + s2 - s1;

                   i++;

                }

            }

            else 

            {

                result = result + s1;

                i++;

            }

        }

        return result;

    }

​

​

    public static void Main() {

​

        Console.Write("Enter the roman numeral: ");

        String input = Console.ReadLine();

​

        ToArabic arabic = new ToArabic();

        Console.Write("In arabic: " + arabic.ToDecimal(input));

    }

}