#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e5+10,M = 30,K = 26,INF = 1e9;
template<typename T>void tomin(T& x,T y){x = min(x,y);}
template<typename T>void tomax(T& x,T y){x = max(x,y);}
//
string A[4] = {"","M","MM","MMM"},B[10],C[10],D[10];
void gen(string* s,string I,string V,string X){
    s[0] = "";
    s[1] = I; s[2] = I+I; s[3] = I+I+I;
    s[4] = I+V; s[5] = V; s[6] = V+I;
    s[7] = V+I+I; s[8] = V+I+I+I; s[9] = I+X;
}
int ch[M][K],dep[M],tag[M],tot; queue<int> qu;
 
string s;
int dp[N][M],pre[N],n; 

int main(){ 
    ios::sync_with_stdio(false); cin.tie(0);
    gen(B,"C","D","M"); gen(C,"X","L","C"); gen(D,"I","V","X");
    for(int a=0;a<4;a++)for(int b=0;b<10;b++)for(int c=0;c<10;c++)for(int d=0;d<10;d++){
        string s = A[a] + B[b] + C[c] + D[d],rs = s;
        reverse(rs.begin(),rs.end());
        if(s != rs || s == "")continue;
        int u = 0,len = s.length();
        for(int i=0;i<len;i++){
            int& v = ch[u][s[i]-'A'];
            if(!v)v = ++tot,dep[v] = dep[u] + 1;
            u = v;
        }
        tag[u] = 1;
    }
    //
    cin>>n>>s; s=" "+s;
    for(int i=1;i<=n+1;i++)for(int j=0;j<=tot;j++)dp[i][j] = INF;
    dp[1][0] = 0;
    for(int i=1;i<=n;i++){
        for(int j=0;j<=tot;j++){
            int w = dp[i][j]; if(w==INF)continue;
            int nj = ch[j][s[i]-'A']; if(!nj)continue;
            tomin(dp[i+1][nj],w);
            if(tag[nj]){
                if(dp[i+1][0] > w+1){
                    dp[i+1][0] = w+1;
                    pre[i+1] = dep[nj];
                }
            }
        }
    }
    cout<<dp[n+1][0]<<"\n";
    vector<string> ans;
    int R = n+1;
    while(R>1){
        int len = pre[R];
        string now; for(int j=R-len;j<R;j++)now.append(1,s[j]);
        ans.push_back(now);
        R -= len;
    }
    reverse(ans.begin(),ans.end());
    for(auto s : ans)cout<<s<<"\n";

    return 0;
}