#include<cstdio>
#include <iostream>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>

using namespace std;
typedef long long ll;
typedef pair<int, int> Pr;

int N;
ll sum;

int main()
{
	cin >> N;
	for (int i = 0; i < N; i++) {
		string s;
		cin >> s;
		for (int j = 0; j < s.size(); j++) {
			if (s[j] == 'I') {
				if (j + 1 < s.size()) {
					if (s[j + 1] == 'X')sum += 9, j++;
					else if (s[j + 1] == 'V')sum += 4, j++;
					else sum++;
				}
				else sum++;
			}
			else if (s[j] == 'V')sum += 5;
			else if (s[j] == 'X' ){
				if(j + 1 < s.size()) {
					if (s[j + 1] == 'L')sum += 40, j++;
					else if (s[j + 1] == 'C')sum += 90, j++;
					else sum += 10;
				}
				else sum += 10;
			}
			
			else if (s[j] == 'L')sum += 50;
			else if (s[j] == 'C') {
				if(j + 1 < s.size()) {
					if (s[j + 1] == 'D')sum += 400, j++;
					else if (s[j + 1] == 'M')sum += 900, j++;
					else sum += 100;
				}
				else sum += 100;
			}

			else if (s[j] == 'D')sum += 500;
			else if (s[j] == 'M')sum += 1000;
		}
	}
	if (sum > 3999) {
		cout << "ERROR" << endl;
	}
	else {
		int m = sum / 1000;
		sum -= m * 1000;
		for (int i = 0; i < m; i++)
			cout << "M";
		int c = sum / 100;
		if (c <= 3) {
			for (int i = 0; i < c; i++)
				cout << "C";
			sum -= c * 100;
		}else{
			if (c == 4)cout << "CD", sum -= 400;
			else if (c == 5)cout << "D", sum -= 500;
			else if (c == 6)cout << "DC", sum -= 600;
			else if (c == 7)cout << "DCC", sum -= 700;
			else if (c == 8)cout << "DCCC", sum -= 800;
			else if (c == 9)cout << "CM", sum -= 900;
		}
		int x = sum / 10;
		if (x <= 3) {
			for (int i = 0; i < x; i++)
				cout << "X";
			sum -= x * 10;
		}
		else {
			if (x == 4)cout << "XL", sum -= 40;
			else if (x == 5)cout << "L", sum -= 50;
			else if (x == 6)cout << "LX", sum -= 60;
			else if (x == 7)cout << "LXX", sum -= 70;
			else if (x == 8)cout << "LXXX", sum -= 80;
			else if (x == 9)cout << "XC", sum -= 90;
		}
		if (sum <= 3) {
			for (int i = 0; i < sum; i++)
				cout << "I";
		}else{
			if (sum == 4)cout << "IV";
			else if (sum == 5)cout << "V";
			else if (sum == 6)cout << "VI";
			else if (sum == 7)cout << "VII";
			else if (sum == 8)cout << "VIII";
			else if (sum == 9)cout << "IX";
		}
		cout << endl;
	}
	return	0;
}