#include using namespace std; #define FOR(i,a,b) for(int i=(a);i<(b);++i) #define REP(i,n) FOR(i,0,n) #define ALL(v) begin(v),end(v) template inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; } using ll = long long; using pii = pair; constexpr ll INF = 1ll<<30; constexpr ll longINF = 1ll<<60; constexpr ll MOD = 1000000007; constexpr bool debug = false; //---------------------------------// int main() { int N; cin >> N; int num[] = {1, 5, 10, 50, 100, 500, 1000}; string roma = "IVXLCDM"; map conv; REP(i, roma.size()) conv[roma[i]] = i; auto decode = [&](const string & R) -> int { int res = 0, prv = INF; REP(i, R.size()) { int cur = num[conv[R[i]]]; if (prv < cur) { res += cur - prv; prv = INF; } else if (prv == cur) prv += cur; else { if (prv != INF) res += prv; prv = cur; } } if (prv != INF) res += prv; return res; }; auto encode = [&](int n) -> string { string res; for (int i = 6; i >= 0; --i) { int cur = n / num[i]; n -= cur * num[i]; if (cur == 4) { res += "I"; res += roma[i]; } else res += string(cur, roma[i]); } return res; }; int ans = 0; REP(i, N) { string s; cin >> s; ans += decode(s); } if (ans > 3999) puts("ERROR"); else cout << encode(ans) << endl; }