X1 = [(),(0,),(0,0),(0,0,0),(0,1),(1,),(1,0),(1,0,0),(1,0,0,0),(0,2)]
X2 = [("I","V","X"),("X","L","C"),("C","D","M"),("M",)]

def decode(S):
    i = 0
    ret = 0
    st = 0
    N = len(S)
    j = N-1
    while 0 <= j:
        s = S[j]
        if st == 0:
            if s == X2[i][0]:
                ret += 10 ** i
                j -= 1
            elif s == X2[i][1]:
                st = 1
                ret += 5 * 10 ** i
                j -= 1
            elif s == X2[i][2]:
                st = 1
                ret += 10 ** (i + 1)
                j -= 1
            else:
                i += 1
        elif st == 1:
            if s == X2[i][0]:
                ret -= 10 ** i
                j -= 1
            st = 0
            i += 1
    return ret

def encode(x):
    ret = []
    if x > 3999:
        print("ERROR")
        exit()
    i = 0
    while x > 0:
        a = x % 10
        tmp = ""
        for j in X1[a]:
            tmp += X2[i][j]
        ret.append(tmp)
        i += 1
        x //= 10
    return "".join(ret[::-1])

N = int(input())
R = input().split()
print(encode(sum([decode(r) for r in R])))