#include<iostream>
using namespace std;
int f(const string&s)
{
	int ret=0;
	int pre=-114514;
	for(int i=0;i<s.size();i++)
	{
		switch(s[i]){
			case'I':ret+=1;pre=1;break;
			case'V':ret+=pre==1?3:5;pre=5;break;
			case'X':ret+=pre==1?8:10;pre=10;break;
			case'L':ret+=pre==10?30:50;pre=50;break;
			case'C':ret+=pre==10?80:100;pre=100;break;
			case'D':ret+=pre==100?300:500;pre=500;break;
			case'M':ret+=pre==100?800:1000;pre=1000;break;
		}
	}
	return ret;
}
string g(char a,char b,char c,int t)
{
	string ret="";
	if(t<4)
	{
		for(int i=0;i<t;i++)ret+=a;
	}
	else if(t==4)ret+=a,ret+=b;
	else if(t<9)
	{
		ret+=b;
		for(int i=5;i<t;i++)ret+=a;
	}
	else ret+=a,ret+=c;
	return ret;
}
main()
{
	int N;cin>>N;
	int ans=0;
	for(;N--;)
	{
		string s;cin>>s;ans+=f(s);
	}
	if(ans>=4000)
	{
		cout<<"ERROR"<<endl;
		return 0;
	}
	string ret="";
	if(ans/1000)ret+=g('M','0','0',ans/1000);
	ans%=1000;
	if(ans/100)ret+=g('C','D','M',ans/100);
	ans%=100;
	if(ans/10)ret+=g('X','L','C',ans/10);
	ans%=10;
	if(ans)ret+=g('I','V','X',ans);
	cout<<ret<<endl;
}