#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;

#define REP(i,n) for(long long i = 0; i < (n); i++)
#define FOR(i, m, n) for(long long i = (m);i < (n); ++i)
#define ALL(obj) (obj).begin(),(obj).end()
#define SPEED cin.tie(0);ios::sync_with_stdio(false);

template<class T> using V = vector<T>;
template<class T, class U> using P = pair<T, U>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQR = priority_queue<T,vector<T>,greater<T>>;

constexpr long long MOD = (long long)1e9 + 7;
constexpr long long MOD2 = 998244353;
constexpr long long HIGHINF = (long long)1e18;
constexpr long long LOWINF = (long long)1e15;
constexpr long double PI = 3.1415926535897932384626433;

template <class T> vector<T> make_v(size_t N,T init){return vector<T>(N,init);}
template <class... T> auto make_v(size_t N,T... t){return vector<decltype(make_v(t...))>(N,make_v(t...));}
template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}}
template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;}
template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;}
template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
void print(void) {cout << endl;}
template <class Head> void print(Head&& head) {cout << head;print();}
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);}
template <class T> void chmax(T& a, const T b){a=max(a,b);}
template <class T> void chmin(T& a, const T b){a=min(a,b);}
void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;}
void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;}
void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;}


int Longest_Common_Subsequence_Size(const string& S, const string& T){
	vector<vector<int>> res(S.size()+1,V<int>(T.size()+1,0));
    for(size_t i = 0; i < S.size(); i++)
    for(size_t j = 0; j < T.size(); j++)
    res[i+1][j+1] = (S[i] == T[j] ? res[i][j] + 1 : max(res[i][j + 1],res[i + 1][j]) );
    return res[S.size()][T.size()];
}

vector<int> ZAlgorithm(const string str) {
	int N = str.size();
	vector<int> res(N);
	for(int i = 1, j = 0; i < N; i++) {
		if(i + res[i - j] < j + res[j]) {
			res[i] = res[i - j];
		} 
		else {
			int k = max(0, j + res[j] - i);
			while(i + k < N && str[k] == str[i + k]) ++k;
			res[j = i] = k;
		}
	}
	res[0] = N;
	return res;
}

int main() {
    int N; cin >> N;
    string S,T; cin >> S;
    T.push_back(S.back());
    S.pop_back();
    int ans = 0;
    while(S.size() && T.size()) {
        auto v = ZAlgorithm(T+"#"+S);
        int cnt = 0;
        for(int i = T.size()+1; i < N+1; ++i) chmax(cnt,v[i]);
        chmax(ans,cnt);
        char c = S.back();
        S.pop_back();
        T = c + T;
    }
    cout << ans << endl;

    return 0;
}


Measured memory_bytes: 256