#include<bits/stdc++.h>
#include<cstdio>
using namespace std;
ifstream fin("password.in");
ofstream fout("password.out");
string s;
struct ans
{
    int num;
    int br;
};
vector<ans>v;

int maxn;
int main()
{
    int n,i,j;
    fin>>n;
    fin>>s;
    for(i=0;i<n;i++)
    {
        for(j=i;j<n;j++)
        {
            if(i==n-1||s[j]!=s[i])break;
        }
        if(j==n-1&&s[i]==s[j])j++;
        ans a;
        a.br=j-i;
        a.num=s[i]-'0';
        if(a.br>maxn)v.clear();
        if(a.br>=maxn)
        {
            maxn=a.br;
            v.push_back(a);
        }
        if(j==n)break;
        i=j-1;
    }
    fout<<v.size()<<endl;
    for(i=0;i<v.size();i++)
    {
        for(j=0;j<v[i].br;j++)fout<<v[i].num;
        fout<<endl;
    }
    return 0;
}