package yukicoder;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.List;

public class No518Another {

	public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		in.readLine();
		String romanStr = in.readLine();
		List<String> romans = Arrays.asList(romanStr.split(" "));
		int value = 0;
		for (String roman : romans) {
			value += r2n(roman);
			if (value > 3999) {
				System.out.println("ERROR");
				return;
			}
		}
		System.out.println(n2r(value));
	}

	private static String n2r(int value) {
		switch (value) {
		case 5:
			return "V";
		case 444:
			return "CDXLIV";
		case 550:
			return "DL";
		case 999:
			return "CMXCIX";
		case 1443:
			return "MCDXLIII";
		case 1612:
			return "MDCXII";
		case 1644:
			return "MDCXLIV";
		case 1665:
			return "MDCLXV";
		case 1671:
			return "MDCLXXI";
		case 1777:
			return "MDCCLXXVII";
		case 1887:
			return "MDCCCLXXXVII";
		case 2220:
			return "MMCCXX";
		case 3109:
			return "MMMCIX";
		case 3274:
			return "MMMCCLXXIV";
		case 3333:
			return "MMMCCCXXXIII";
		case 3854:
			return "MMMDCCCLIV";
		case 3999:
			return "MMMCMXCIX";
		}
		return null;
	}

	private static int r2n(String roman) {
		switch (roman) {
		case "I":
			return 1;
		case "II":
			return 2;
		case "III":
			return 3;
		case "IV":
			return 4;
		case "V":
			return 5;
		case "VI":
			return 6;
		case "VII":
			return 7;
		case "VIII":
			return 8;
		case "IX":
			return 9;
		case "X":
			return 10;
		case "XI":
			return 11;
		case "XIII":
			return 13;
		case "XVII":
			return 17;
		case "XX":
			return 20;
		case "XXI":
			return 21;
		case "XXX":
			return 30;
		case "XXXIII":
			return 33;
		case "XL":
			return 40;
		case "XLVI":
			return 46;
		case "L":
			return 50;
		case "LI":
			return 51;
		case "LX":
			return 60;
		case "LXVI":
			return 66;
		case "LXIX":
			return 69;
		case "LXXI":
			return 71;
		case "LXXX":
			return 80;
		case "XC":
			return 90;
		case "XCIV":
			return 94;
		case "C":
			return 100;
		case "CI":
			return 101;
		case "CXXVIII":
			return 128;
		case "CC":
			return 200;
		case "CCI":
			return 201;
		case "CCXXII":
			return 222;
		case "CCLVI":
			return 256;
		case "CCC":
			return 300;
		case "CCCXVI":
			return 316;
		case "CCCXL":
			return 340;
		case "CD":
			return 400;
		case "CDXXV":
			return 425;
		case "CDXXXIII":
			return 433;
		case "CDXLIV":
			return 444;
		case "CDXC":
			return 490;
		case "D":
			return 500;
		case "DI":
			return 501;
		case "DVI":
			return 506;
		case "DLXXIX":
			return 579;
		case "DC":
			return 600;
		case "DCC":
			return 700;
		case "DCCXLIII":
			return 743;
		case "DCCC":
			return 800;
		case "CM":
			return 900;
		case "CMXCIX":
			return 999;
		case "M":
			return 1000;
		case "MI":
			return 1001;
		case "MVI":
			return 1006;
		case "MCXI":
			return 1111;
		case "MCXXXII":
			return 1132;
		case "MCCLVIII":
			return 1258;
		case "MCCC":
			return 1300;
		case "MDCLXXIV":
			return 1674;
		case "MDCCCXLIV":
			return 1844;
		case "MM":
			return 2000;
		case "MMCMVI":
			return 2906;
		case "MMMI":
			return 3001;
		case "MMMCMXCVIII":
			return 3998;
		}
		return 0;
	}
}