using System;
using System.Linq;
using System.Collections.Generic;
using Debug = System.Diagnostics.Debug;
using SB = System.Text.StringBuilder;
using Number = System.Int64;
//using System.Numerics;
//using static System.Math;
//using static MathEx;
//using P = System.Collections.Generic.KeyValuePair<int, int>;
namespace Program
{
    public class Solver
    {
        public void Solve()
        {
            var n = ri;
            var a = Enumerate(n, x => f(rs));
            Debug.WriteLine(a.AsJoinedString());
            var v = a.Sum();
            IO.Printer.Out.WriteLine(g(v));


        }
        string g(int x)
        {
            Debug.WriteLine(x);
            if (x >= 4000) return "ERROR";
            var s = "";
            while (x >= 1000) { x -= 1000; s += "M"; }
            if (x >= 900) { x -= 900; s += "CM"; }
            if (x >= 500) { x -= 500; s += "D"; }
            if (x >= 400) { x -= 400; s += "CD"; }
            while (x >= 100) { x -= 100; s += "C"; }
            if (x >= 90) { x -= 90; s += "XC"; }
            if (x >= 50) { x -= 50; s += "L"; }
            if (x >= 40) { x -= 40; s += "XL"; }
            while (x >= 10) { x -= 10; s += "X"; }
            if (x >= 9) { x -= 9; s += "IX"; }
            if (x >= 5) { x -= 5; s += "V"; }
            if (x >= 4) { x -= 4; s += "IV"; }
            while (x >= 1) { x -= 1; s += "I"; }

            return s;
        }
        int f(string s)
        {
            var ret = 0;
            ret += s.Count(x => x == 'I');
            ret += s.Count(x => x == 'V') * 5;
            ret += s.Count(x => x == 'X') * 10;
            ret += s.Count(x => x == 'L') * 50;
            ret += s.Count(x => x == 'C') * 100;
            ret += s.Count(x => x == 'D') * 500;
            ret += s.Count(x => x == 'M') * 1000;
            for (int i = 1; i < s.Length; i++)
            {
                var p = s[i - 1];
                var c = s[i];
                if (p == 'I' && c == 'V') ret -= 2;
                if (p == 'I' && c == 'X') ret -= 2;
                if (p == 'X' && c == 'L') ret -= 20;
                if (p == 'X' && c == 'C') ret -= 20;
                if (p == 'C' && c == 'D') ret -= 200;
                if (p == 'C' && c == 'M') ret -= 200;
            }

            return ret;
        }
        //*
        int ri => sc.Integer();
        long rl => sc.Long();
        double rd => sc.Double();
        string rs => sc.Scan();
        char rc => sc.Char();

        [System.Diagnostics.Conditional("DEBUG")]
        void put(params object[] a) => Debug.WriteLine(string.Join(" ", a));
        //*/
        public IO.StreamScanner sc = new IO.StreamScanner(Console.OpenStandardInput());
        static T[] Enumerate<T>(int n, Func<int, T> f) { var a = new T[n]; for (int i = 0; i < n; ++i) a[i] = f(i); return a; }
        static public void Swap<T>(ref T a, ref T b) { var tmp = a; a = b; b = tmp; }
    }
}

#region main
static class Ex
{
    static public string AsString(this IEnumerable<char> ie) { return new string(System.Linq.Enumerable.ToArray(ie)); }
    static public string AsJoinedString<T>(this IEnumerable<T> ie, string st = " ") { return string.Join(st, ie); }
    static public void Main()
    {
        var solver = new Program.Solver();
        solver.Solve();
        Program.IO.Printer.Out.Flush();
    }
}
#endregion
#region Ex
namespace Program.IO
{
    using System.IO;
    using System.Text;
    using System.Globalization;
    public class Printer: StreamWriter
    {
        static Printer() { Out = new Printer(Console.OpenStandardOutput()) { AutoFlush = false }; }
        public static Printer Out { get; set; }
        public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } }
        public Printer(System.IO.Stream stream) : base(stream, new UTF8Encoding(false, true)) { }
        public Printer(System.IO.Stream stream, Encoding encoding) : base(stream, encoding) { }
        public void Write<T>(string format, T[] source) { base.Write(format, source.OfType<object>().ToArray()); }
        public void WriteLine<T>(string format, T[] source) { base.WriteLine(format, source.OfType<object>().ToArray()); }
    }
    public class StreamScanner
    {
        public StreamScanner(Stream stream) { str = stream; }
        public readonly Stream str;
        private readonly byte[] buf = new byte[1024];
        private int len, ptr;
        public bool isEof = false;
        public bool IsEndOfStream { get { return isEof; } }
        private byte read()
        {
            if (isEof) return 0;
            if (ptr >= len) { ptr = 0; if ((len = str.Read(buf, 0, 1024)) <= 0) { isEof = true; return 0; } }
            return buf[ptr++];
        }
        public char Char() { byte b = 0; do b = read(); while ((b < 33 || 126 < b) && !isEof); return (char)b; }

        public string Scan()
        {
            var sb = new StringBuilder();
            for (var b = Char(); b >= 33 && b <= 126; b = (char)read())
                sb.Append(b);
            return sb.ToString();
        }
        public string ScanLine()
        {
            var sb = new StringBuilder();
            for (var b = Char(); b != '\n'; b = (char)read())
                if (b == 0) break;
                else if (b != '\r') sb.Append(b);
            return sb.ToString();
        }
        public long Long()
        {
            if (isEof) return long.MinValue;
            long ret = 0; byte b = 0; var ng = false;
            do b = read();
            while (b != 0 && b != '-' && (b < '0' || '9' < b));
            if (b == 0) return long.MinValue;
            if (b == '-') { ng = true; b = read(); }
            for (; true; b = read())
            {
                if (b < '0' || '9' < b)
                    return ng ? -ret : ret;
                else ret = ret * 10 + b - '0';
            }
        }
        public int Integer() { return (isEof) ? int.MinValue : (int)Long(); }
        public double Double() { var s = Scan(); return s != "" ? double.Parse(s, CultureInfo.InvariantCulture) : double.NaN; }
        private T[] enumerate<T>(int n, Func<T> f)
        {
            var a = new T[n];
            for (int i = 0; i < n; ++i) a[i] = f();
            return a;
        }

        public char[] Char(int n) { return enumerate(n, Char); }
        public string[] Scan(int n) { return enumerate(n, Scan); }
        public double[] Double(int n) { return enumerate(n, Double); }
        public int[] Integer(int n) { return enumerate(n, Integer); }
        public long[] Long(int n) { return enumerate(n, Long); }
    }
}
#endregion