using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Globalization;
using System.Diagnostics;
using static System.Console;
using Pair = System.Collections.Generic.KeyValuePair<int, int>;
//using System.Numerics;

class Program
{
    static void Main()
    {
        //SetOut(new StreamWriter(OpenStandardOutput()) { AutoFlush = false });
        new Program().Solve();
        Out.Flush();
    }
    Scanner cin = new Scanner();
    Random rnd = new Random();
    Stopwatch sw = new Stopwatch();
    readonly int[] dd = { 0, 1, 0, -1, 0 };
    readonly int mod = 1000000007;
    readonly string alfa = "abcdefghijklmnopqrstuvwxyz";

  
    string[][] roman_nums = new string[][] { new[] { "", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX" }, new[] { "", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC" }, new[]{ "", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM" }, new[] { "", "M", "MM", "MMM" } };
    void Solve()
    {
        int N = cin.Nextint;
        int sum = 0;
        for (int i = 0; i < N; i++)
        {
            var R = cin.Next;
            int yon = 0, san = 0, ni = 0, iti = 0;

            int j = 0;
            var S = "";
            while (j < R.Length && R[j] == 'M')
            {
                S += R[j];
                j++;
            }
            yon = Array.IndexOf(roman_nums[3], S);
            S = "";
            while (j < R.Length && (R[j] == 'C' || R[j] == 'D' || R[j] == 'M'))
            {
                S += R[j];
                j++;
            }
            san = Array.IndexOf(roman_nums[2], S);
            S = "";
            while (j < R.Length && (R[j] == 'C' || R[j] == 'X' || R[j] == 'L'))
            {
                S += R[j];
                j++;
            }
            ni = Array.IndexOf(roman_nums[1], S);
            S = "";
            while (j < R.Length)
            {
                S += R[j];
                j++;
            }
            iti = Array.IndexOf(roman_nums[0], S);

            sum += 1000 * yon + 100 * san + 10 * ni + iti;
            if(sum > 3999)
            {
                WriteLine("ERROR");
                return;
            }
        }
        string ans = "";
        ans += roman_nums[3][sum / 1000];
        sum %= 1000;
        ans += roman_nums[2][sum / 100];
        sum %= 100;
        ans += roman_nums[1][sum / 10];
        sum %= 10;
        ans += roman_nums[0][sum];

        WriteLine(ans);
    }

}

class Scanner
{
    string[] s; int i;
    char[] cs = new char[] { ' ' };
    public Scanner() { s = new string[0]; i = 0; }
    public string[] Scan { get { return ReadLine().Split(); } }
    public int[] Scanint { get { return Array.ConvertAll(Scan, int.Parse); } }
    public long[] Scanlong { get { return Array.ConvertAll(Scan, long.Parse); } }
    public double[] Scandouble { get { return Array.ConvertAll(Scan, double.Parse); } }
    public string Next
    {
        get
        {
            if (i < s.Length) return s[i++];
            string st = ReadLine();
            while (st == "") st = ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            i = 0;
            return Next;
        }
    }
    public int Nextint { get { return int.Parse(Next); } }
    public long Nextlong { get { return long.Parse(Next); } }
    public double Nextdouble { get { return double.Parse(Next); } }
}