#include <bits/stdc++.h>

using namespace std;

const string S1[] = {"", "M", "MM", "MMM"},
             S2[] = {"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"},
             S3[] = {"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"},
             S4[] = {"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"};

string convert(int x) {
    int a = x / 1000, b = x / 100 % 10, c = x / 10 % 10, d = x % 10;
    return S1[a] + S2[b] + S3[c] + S4[d];
}

map<string, int> vis;

const int N = 1e5 + 5;

int f[N], g[N];

signed main() {
    for (int i = 1; i <= 3999; ++i) {
        string str = convert(i), tstr = str;
        reverse(tstr.begin(), tstr.end());
        if (tstr == str) vis[str] = 1;
    }
    int n; scanf("%d", &n);
    string S; cin >> S;
    S = ' ' + S;
    for (int i = 1; i <= n; ++i) {
        f[i] = 1e9;
        for (int j = max(i - 3, 0); j < i; ++j) {
            if (vis[S.substr(j + 1, i - j)] && f[j] + 1 < f[i]) {
                f[i] = f[j] + 1, g[i] = j;
            }
        }
    }
    vector<string> res;
    for (int i = n; i; i = g[i]) {
        res.push_back(S.substr(g[i] + 1, i - g[i]));
    }
    reverse(res.begin(), res.end());
    printf("%d\n", (int)res.size());
    for (auto s : res) puts(s.c_str());
    return 0;
}