using System;

public class Program

{

    public static void Main()

    {

        Program p = new Program();

        Console.WriteLine(p.RomanToInt("I"));

        Console.WriteLine(p.RomanToInt("II"));

        Console.WriteLine(p.RomanToInt("IV"));

        Console.WriteLine(p.RomanToInt("VI"));

        Console.WriteLine(p.RomanToInt("IX"));

        Console.WriteLine(p.RomanToInt("IIX"));

    }

    public int RomanToInt(string numeral)

    {

        int[] lookup = new int['X'+1]; 

        lookup['I'] = 1;

        lookup['V'] = 5;

        lookup['X'] = 10;

        lookup['L'] = 50;

        lookup['C'] = 100;

        lookup['D'] = 500;

        lookup['M'] = 1000;

        int totalValue = 0;

        int currentValue = 0;

        int i;

        for (i = 0; i < numeral.Length - 1; i++)

        {

            currentValue = lookup[numeral[i]];

            if (currentValue < lookup[numeral[i+1]])

            {

                totalValue += lookup[numeral[i + 1]] - currentValue;

                i++;

            }

            else

            {

                totalValue += currentValue;

            }

        }

        if (i < numeral.Length)

            totalValue += lookup[numeral[numeral.Length - 1]];

        return totalValue;

    }

}