import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


enum L = 13;
enum S = ["I", "IV", "V", "IX", "X", "XL", "L", "XC", "C", "CD", "D", "CM", "M"];
enum X = [1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900, 1000];
int[string] tr;

int romanToArabic(string s) {
  
  const len = cast(int)(s.length);
  int x;
  for (int i = 0; i < len; ) {
    if (i + 2 <= len && s[i .. i + 2] in tr) {
      x += tr[s[i .. i + 2]];
      i += 2;
    } else {
      assert(s[i .. i + 1] in tr);
      x += tr[s[i .. i + 1]];
      i += 1;
    }
  }
  return x;
}

string arabicToRoman(int x) {
  string s;
  foreach_reverse (l; 0 .. L) {
    for (; x >= X[l]; ) {
      s ~= S[l];
      x -= X[l];
    }
  }
  assert(x == 0);
  return s;
}

void main() {
  foreach (l; 0 .. L) {
    tr[S[l]] = X[l];
  }
  
  try {
    for (; ; ) {
      const N = readInt();
      auto R = new string[N];
      foreach (i; 0 .. N) {
        R[i] = readToken();
      }
      
      int sum;
      foreach (i; 0 .. N) {
        sum += romanToArabic(R[i]);
      }
      if (sum > 3999) {
        writeln("ERROR");
      } else {
        writeln(arabicToRoman(sum));
      }
    }
  } catch (EOFException e) {
  }
}