import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.io.OutputStream;
import java.util.StringTokenizer;
import java.io.BufferedReader;
import java.io.InputStreamReader;
/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Task solver = new Task();
        solver.solve(1, in, out);
        out.close();
    }

    static class Task {
        public void solve(int testNumber, InputReader in, PrintWriter out) {
            int N = in.nextInt();
            String a[] = new String[N];
            int b[] = new int[N];
            for(int i=0; i<N; i++){
                a[i] = in.next();
                for(int j=0; j<a[i].length(); j++){
                    if(j==a[i].length()-1){
                        if(a[i].charAt(j)=='I') b[i]+=1;
                        else if(a[i].charAt(j)=='V') b[i]+=5;
                        else if(a[i].charAt(j)=='X') b[i]+=10;
                        else if(a[i].charAt(j)=='L') b[i]+=50;
                        else if(a[i].charAt(j)=='C') b[i]+=100;
                        else if(a[i].charAt(j)=='D') b[i]+=500;
                        else if(a[i].charAt(j)=='M') b[i]+=1000;

                    }
                    else{
                        if(a[i].charAt(j)=='I'){
                            if(a[i].charAt(j+1)=='V'){
                                b[i]+=4;
                                j++;
                            }
                            else if(a[i].charAt(j+1)=='X'){
                                b[i]+=9;
                                j++;
                            }
                            else b[i]+=1;
                        }
                        else if(a[i].charAt(j)=='X'){
                            if(a[i].charAt(j+1)=='L'){
                                b[i]+=40;
                                j++;
                            }
                            else if(a[i].charAt(j+1)=='C'){
                                b[i]+=90;
                                j++;
                            }
                            else b[i]+=10;
                        }
                        else if(a[i].charAt(j)=='C'){
                            if(a[i].charAt(j+1)=='D'){
                                b[i]+=400;
                                j++;
                            }
                            else if(a[i].charAt(j+1)=='M'){
                                b[i]+=900;
                                j++;
                            }
                            else b[i]+=100;
                        }
                        else if(a[i].charAt(j)=='V') b[i]+=5;
                        else if(a[i].charAt(j)=='L') b[i]+=50;
                        else if(a[i].charAt(j)=='D') b[i]+=500;
                        else if(a[i].charAt(j)=='M') b[i]+=1000;
                    }
                }
            }
            int res=0;

            for(int i=0; i<N;i++){
                res+=b[i];
            }

            if(res>3999){
                out.println("ERROR");
                return;
            }
            int v;

            while(res>0){
                if(res>=1000){
                    v=res/1000;
                    if(v<4){
                        res -= v*1000;
                        for(int i=0; i<v; i++) out.print("M");
                    }
                }
                if(res>=100){
                    v=res/100;
                    res -= v*100;
                    if(v<4){
                        for(int i=0; i<v; i++) out.print("C");
                    }
                    else if(v==4) out.print("CD");
                    else if(v<9){
                        out.print("D");
                        for(int i=0; i<v-5; i++){
                            out.print("C");
                        }
                    }
                    else out.print("CM");
                }
                if(res>=10){
                    v=res/10;
                    res -= v*10;
                    if(v<4){
                        for(int i=0; i<v; i++) out.print("X");
                    }
                    else if(v==4) out.print("XL");
                    else if(v<9){
                        out.print("L");
                        for(int i=0; i<v-5; i++){
                            out.print("X");
                        }
                    }
                    else out.print("XC");
                }
                if(res>=1){
                    v=res/1;
                    res -= v*1;
                    if(v<4){
                        for(int i=0; i<v; i++) out.print("I");
                    }
                    else if(v==4) out.print("IV");
                    else if(v<9){
                        out.print("V");
                        for(int i=0; i<v-5; i++){
                            out.print("I");
                        }
                    }
                    else out.print("IX");
                }
            }
            
        }
    }

    static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

    }
}