#include <bits/stdc++.h>
using namespace std;

string dec2rome(int n) {
    if (n >= 1000) {
        return "M" + dec2rome(n - 1000);
    } else if (n >= 900) {
        return "CM" + dec2rome(n - 900);
    } else if (n >= 500) {
        return "D" + dec2rome(n - 500);
    } else if (n >= 400) {
        return "CD" + dec2rome(n - 400);
    } else if (n >= 100) {
        return "C" + dec2rome(n - 100);
    } else if (n >= 90) {
        return "XC" + dec2rome(n - 90);
    } else if (n >= 50) {
        return "L" + dec2rome(n - 50);
    } else if (n >= 40) {
        return "XL" + dec2rome(n - 40);
    } else if (n >= 10) {
        return "X" + dec2rome(n - 10);
    } else if (n >= 9) {
        return "IX" + dec2rome(n - 9);
    } else if (n >= 5) {
        return "V" + dec2rome(n - 5);
    } else if (n >= 4) {
        return "IV" + dec2rome(n - 4);
    } else if (n >= 1) {
        return "I" + dec2rome(n - 1);
    } else {
        return "";
    }
}

int rome2dec(string s) {
    map<char, int> m;
    m['I'] = 1;
    m['V'] = 5;
    m['X'] = 10;
    m['L'] = 50;
    m['C'] = 100;
    m['D'] = 500;
    m['M'] = 1000;
    int ans = 0, prev = 0;
    for (char c : s) {
        ans += m[c];
        if (m[c] > prev) ans -= 2 * prev;
        prev = m[c];
    }
    return ans;
}

int main() {
    int n, ans = 0;
    cin >> n;
    for (int i = 0; i < n; i++) {
        string r;
        cin >> r;
        ans += rome2dec(r);
    }
    if (ans >= 4000) {
        cout << "ERROR" << endl;
        return 0;
    }
}