#include<iostream>
#include<cstring>
#include<vector>
#include<set>
#include<queue>
using namespace std;
using LL = long long;
int a[1000005], l[1000005], r[1000005];
int v[1000005];

vector<int> s[26 * 26 * 26];

int target[3];
vector<int> del;
int ts;

int check(int x){
    if (v[x] == ts) return 0;
    if (r[x] == 0 or r[r[x]] == 0) return 0;
    if (a[x] != target[0] or a[r[x]] != target[1] or a[r[r[x]]] != target[2]) return 0;
    v[x] = v[r[x]] = v[r[r[x]]] = ts;
    int pre = l[x];
    int nxt = r[r[r[x]]];
    if (pre != 0){
        r[pre] = nxt;
        del.push_back(pre);
    }
    if (nxt != 0){
        del.push_back(nxt);
        l[nxt] = pre;
    }
    int ans = 1;
    if (l[x] != 0 and l[l[x]] != 0){
        int t = check(l[l[x]]);
        ans += t;
        if (t > 0) return ans;
    }
    if (l[x] != 0){
        ans += check(l[x]);
    }
    return ans;
}

int main(){

#ifdef LOCAL
    freopen("data.in", "r", stdin);
    freopen("data.out", "w", stdout);
#endif

    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(0);

    int n;
    cin >> n;
    string str;
    cin >> str;
    for(int i = 1; i <= n; i++){
        a[i] = str[i - 1] - 'a';
        l[i] = i - 1;
        r[i] = i + 1;
    }
    pair<int, int> ans{0, 0};
    for(int i = 1; i + 2 <= n; i++){
        int t = a[i] * 26 * 26 + a[i + 1] * 26 + a[i + 2];
        s[t].push_back(i);
    }
    r[n] = 0;
    for(int i = 0; i < 26 * 26 * 26; i++){
        if (s[i].empty()) continue;
        target[0] = i / (26 * 26);
        target[1] = i % (26 * 26) / 26;
        target[2] = i % 26;
        ++ts;
        int sum = 0;
        for(auto x : s[i]){
            sum += check(x);
        }
        ans = max(ans, pair(sum, -i));
        for(auto x : del){
            l[x] = x - 1;
            r[x] = x + 1;
        }
        del.clear();
    }
    cout << ans.first << '\n';
    int t = -ans.second;
    cout << char('a' + t / (26 * 26)) << char('a' + t % (26 * 26) / 26) << char('a' + t % 26) << '\n';

}