import copy
n = int(input().strip())
nums = input().strip().split()
pri_dic = {"DCCC":800,"LXXX":80,"VIII":8,"MMM":3000,"DCC":700,"CCC":300,"LXX":70,"XXX":30,"VII":7,"III":3,"MM":2000,"CM":900,"DC":600,"CD":400,"CC":200,"XC":90,"LX":60,"XL":40,"XX":20,"IX":9,
        "VI":6,"IV":4,"II":2,"M":1000,"D":500,"C":100,"L":50,"X":10,"V":5,"I":1}
pri_lis = ["DCCC","LXXX","VIII"]
pri_lis2 = ["MMM","DCC","CCC","LXX","XXX","VII","III"]
pri_lis3 = ["MM","CM","DC","CD","CC","XC","LX","XL","XX","IX","VI","IV","II"]
pri_lis4 = ["M","D","C","L","X","V","I"]
def trans(x):
    lis = []
    x2 = copy.deepcopy(x)
    for i in pri_lis:
        if x2[0:4] == i:
            lis.append(pri_dic[i])
            x2 = x2[4:]
    for i in pri_lis2:
        if x2[0:3] == i:
            lis.append(pri_dic[i])
            x2 = x2[3:]
    for i in pri_lis3:
        if x2[0:2] == i:
            lis.append(pri_dic[i])
            x2 = x2[2:]
    for i in pri_lis4:
        if x2[0:1] == i:
            lis.append(pri_dic[i])
            x2 = x2[1:]
    return sum(lis)
nums2 = []
for i in range(n):
    nums2.append(trans(nums[i]))
nums3 = sum(nums2)
def get_key(va):
    return [k for k, v in pri_dic.items() if v == va][0]
nums4 = []
def trans2(x):
    y = str(x)
    l = len(y)
    for i in range(l):
        a = y[-1-i]
        nums4.append(get_key(int(a)*(10**i)))
    nums5 = reversed(nums4)
    return ''.join(nums5)
if nums3 <= 3999:
    print(trans2(nums3))
else:
    print("ERROR")