#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using VI = vector<int>;
using VL = vector<ll>;
using VS = vector<string>;
template<class T> using PQ = priority_queue<T, vector<T>, greater<T>>;
#define FOR(i,a,n) for(int i=(a);i<(n);++i)
#define eFOR(i,a,n) for(int i=(a);i<=(n);++i)
#define rFOR(i,a,n) for(int i=(n)-1;i>=(a);--i)
#define erFOR(i,a,n) for(int i=(n);i>=(a);--i)
#define each(i, a) for(auto &i : a)
#define SORT(a) sort(a.begin(),a.end())
#define rSORT(a) sort(a.rbegin(),a.rend())
#define fSORT(a,f) sort(a.begin(),a.end(),f)
#define all(a) a.begin(),a.end()
#define out(y,x) ((y)<0||h<=(y)||(x)<0||w<=(x))
#define tp(a,i) get<i>(a)
#define line cout << "-----------------------------\n" 
#define ENDL(i,n) ((i) == (n) - 1 ? "\n" : " ")
constexpr ll INF = 1000000000;
constexpr ll LLINF = 1LL << 60;
constexpr ll mod = 1000000007;
constexpr ll MOD = 998244353;
constexpr ld eps = 1e-10;
constexpr ld pi = 3.1415926535897932;
template<class T>inline bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; }return false; }
template<class T>inline bool chmin(T& a, const T& b) { if (a > b) { a = b; return true; }return false; }
inline void init() { cin.tie(nullptr); cout.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); }
template<class T>inline istream& operator>>(istream& is, vector<T>& v) { for (auto& a : v)is >> a; return is; }
template<class T>inline istream& operator>>(istream& is, deque<T>& v) { for (auto& a : v)is >> a; return is; }
template<class T, class U>inline istream& operator>>(istream& is, pair<T, U>& p) { is >> p.first >> p.second; return is; }
template<class T>inline vector<T> vec(size_t a) { return vector<T>(a); }
template<class T>inline vector<T> defvec(T def, size_t a) { return vector<T>(a, def); }
template<class T, class... Ts>inline auto vec(size_t a, Ts... ts) { return vector<decltype(vec<T>(ts...))>(a, vec<T>(ts...)); }
template<class T, class... Ts>inline auto defvec(T def, size_t a, Ts... ts) { return vector<decltype(defvec<T>(def, ts...))>(a, defvec<T>(def, ts...)); }
template<class T>inline void print(const T& a) { cout << a << "\n"; }
template<class T, class... Ts>inline void print(const T& a, const Ts&... ts) { cout << a << " "; print(ts...); }
template<class T>inline void print(const vector<T>& v) { for (int i = 0; i < v.size(); ++i)cout << v[i] << (i == v.size() - 1 ? "\n" : " "); }
template<class T>inline void print(const vector<vector<T>>& v) { for (auto& a : v)print(a); }
inline string reversed(const string& s) { string t = s; reverse(all(t)); return t; }

#ifndef ATCODER_STRING_HPP
#define ATCODER_STRING_HPP 1
namespace atcoder {

    namespace internal {

        std::vector<int> sa_naive(const std::vector<int>& s) {
            int n = int(s.size());
            std::vector<int> sa(n);
            std::iota(sa.begin(), sa.end(), 0);
            std::sort(sa.begin(), sa.end(), [&](int l, int r) {
                if (l == r) return false;
                while (l < n && r < n) {
                    if (s[l] != s[r]) return s[l] < s[r];
                    l++;
                    r++;
                }
                return l == n;
                });
            return sa;
        }

        std::vector<int> sa_doubling(const std::vector<int>& s) {
            int n = int(s.size());
            std::vector<int> sa(n), rnk = s, tmp(n);
            std::iota(sa.begin(), sa.end(), 0);
            for (int k = 1; k < n; k *= 2) {
                auto cmp = [&](int x, int y) {
                    if (rnk[x] != rnk[y]) return rnk[x] < rnk[y];
                    int rx = x + k < n ? rnk[x + k] : -1;
                    int ry = y + k < n ? rnk[y + k] : -1;
                    return rx < ry;
                };
                std::sort(sa.begin(), sa.end(), cmp);
                tmp[sa[0]] = 0;
                for (int i = 1; i < n; i++) {
                    tmp[sa[i]] = tmp[sa[i - 1]] + (cmp(sa[i - 1], sa[i]) ? 1 : 0);
                }
                std::swap(tmp, rnk);
            }
            return sa;
        }

        // SA-IS, linear-time suffix array construction
        // Reference:
        // G. Nong, S. Zhang, and W. H. Chan,
        // Two Efficient Algorithms for Linear Time Suffix Array Construction
        template <int THRESHOLD_NAIVE = 10, int THRESHOLD_DOUBLING = 40>
        std::vector<int> sa_is(const std::vector<int>& s, int upper) {
            int n = int(s.size());
            if (n == 0) return {};
            if (n == 1) return { 0 };
            if (n == 2) {
                if (s[0] < s[1]) {
                    return { 0, 1 };
                }
                else {
                    return { 1, 0 };
                }
            }
            if (n < THRESHOLD_NAIVE) {
                return sa_naive(s);
            }
            if (n < THRESHOLD_DOUBLING) {
                return sa_doubling(s);
            }

            std::vector<int> sa(n);
            std::vector<bool> ls(n);
            for (int i = n - 2; i >= 0; i--) {
                ls[i] = (s[i] == s[i + 1]) ? ls[i + 1] : (s[i] < s[i + 1]);
            }
            std::vector<int> sum_l(upper + 1), sum_s(upper + 1);
            for (int i = 0; i < n; i++) {
                if (!ls[i]) {
                    sum_s[s[i]]++;
                }
                else {
                    sum_l[s[i] + 1]++;
                }
            }
            for (int i = 0; i <= upper; i++) {
                sum_s[i] += sum_l[i];
                if (i < upper) sum_l[i + 1] += sum_s[i];
            }

            auto induce = [&](const std::vector<int>& lms) {
                std::fill(sa.begin(), sa.end(), -1);
                std::vector<int> buf(upper + 1);
                std::copy(sum_s.begin(), sum_s.end(), buf.begin());
                for (auto d : lms) {
                    if (d == n) continue;
                    sa[buf[s[d]]++] = d;
                }
                std::copy(sum_l.begin(), sum_l.end(), buf.begin());
                sa[buf[s[n - 1]]++] = n - 1;
                for (int i = 0; i < n; i++) {
                    int v = sa[i];
                    if (v >= 1 && !ls[v - 1]) {
                        sa[buf[s[v - 1]]++] = v - 1;
                    }
                }
                std::copy(sum_l.begin(), sum_l.end(), buf.begin());
                for (int i = n - 1; i >= 0; i--) {
                    int v = sa[i];
                    if (v >= 1 && ls[v - 1]) {
                        sa[--buf[s[v - 1] + 1]] = v - 1;
                    }
                }
            };

            std::vector<int> lms_map(n + 1, -1);
            int m = 0;
            for (int i = 1; i < n; i++) {
                if (!ls[i - 1] && ls[i]) {
                    lms_map[i] = m++;
                }
            }
            std::vector<int> lms;
            lms.reserve(m);
            for (int i = 1; i < n; i++) {
                if (!ls[i - 1] && ls[i]) {
                    lms.push_back(i);
                }
            }

            induce(lms);

            if (m) {
                std::vector<int> sorted_lms;
                sorted_lms.reserve(m);
                for (int v : sa) {
                    if (lms_map[v] != -1) sorted_lms.push_back(v);
                }
                std::vector<int> rec_s(m);
                int rec_upper = 0;
                rec_s[lms_map[sorted_lms[0]]] = 0;
                for (int i = 1; i < m; i++) {
                    int l = sorted_lms[i - 1], r = sorted_lms[i];
                    int end_l = (lms_map[l] + 1 < m) ? lms[lms_map[l] + 1] : n;
                    int end_r = (lms_map[r] + 1 < m) ? lms[lms_map[r] + 1] : n;
                    bool same = true;
                    if (end_l - l != end_r - r) {
                        same = false;
                    }
                    else {
                        while (l < end_l) {
                            if (s[l] != s[r]) {
                                break;
                            }
                            l++;
                            r++;
                        }
                        if (l == n || s[l] != s[r]) same = false;
                    }
                    if (!same) rec_upper++;
                    rec_s[lms_map[sorted_lms[i]]] = rec_upper;
                }

                auto rec_sa =
                    sa_is<THRESHOLD_NAIVE, THRESHOLD_DOUBLING>(rec_s, rec_upper);

                for (int i = 0; i < m; i++) {
                    sorted_lms[i] = lms[rec_sa[i]];
                }
                induce(sorted_lms);
            }
            return sa;
        }

    }  // namespace internal

    std::vector<int> suffix_array(const std::vector<int>& s, int upper) {
        assert(0 <= upper);
        for (int d : s) {
            assert(0 <= d && d <= upper);
        }
        auto sa = internal::sa_is(s, upper);
        return sa;
    }

    template <class T> std::vector<int> suffix_array(const std::vector<T>& s) {
        int n = int(s.size());
        std::vector<int> idx(n);
        iota(idx.begin(), idx.end(), 0);
        sort(idx.begin(), idx.end(), [&](int l, int r) { return s[l] < s[r]; });
        std::vector<int> s2(n);
        int now = 0;
        for (int i = 0; i < n; i++) {
            if (i && s[idx[i - 1]] != s[idx[i]]) now++;
            s2[idx[i]] = now;
        }
        return internal::sa_is(s2, now);
    }

    std::vector<int> suffix_array(const std::string& s) {
        int n = int(s.size());
        std::vector<int> s2(n);
        for (int i = 0; i < n; i++) {
            s2[i] = s[i];
        }
        return internal::sa_is(s2, 255);
    }

    // Reference:
    // T. Kasai, G. Lee, H. Arimura, S. Arikawa, and K. Park,
    // Linear-Time Longest-Common-Prefix Computation in Suffix Arrays and Its
    // Applications
    template <class T>
    std::vector<int> lcp_array(const std::vector<T>& s,
        const std::vector<int>& sa) {
        int n = int(s.size());
        assert(n >= 1);
        std::vector<int> rnk(n);
        for (int i = 0; i < n; i++) {
            rnk[sa[i]] = i;
        }
        std::vector<int> lcp(n - 1);
        int h = 0;
        for (int i = 0; i < n; i++) {
            if (h > 0) h--;
            if (rnk[i] == 0) continue;
            int j = sa[rnk[i] - 1];
            for (; j + h < n && i + h < n; h++) {
                if (s[j + h] != s[i + h]) break;
            }
            lcp[rnk[i] - 1] = h;
        }
        return lcp;
    }

    std::vector<int> lcp_array(const std::string& s, const std::vector<int>& sa) {
        int n = int(s.size());
        std::vector<int> s2(n);
        for (int i = 0; i < n; i++) {
            s2[i] = s[i];
        }
        return lcp_array(s2, sa);
    }

    // Reference:
    // D. Gusfield,
    // Algorithms on Strings, Trees, and Sequences: Computer Science and
    // Computational Biology
    template <class T> std::vector<int> z_algorithm(const std::vector<T>& s) {
        int n = int(s.size());
        if (n == 0) return {};
        std::vector<int> z(n);
        z[0] = 0;
        for (int i = 1, j = 0; i < n; i++) {
            int& k = z[i];
            k = (j + z[j] <= i) ? 0 : std::min(j + z[j] - i, z[i - j]);
            while (i + k < n && s[k] == s[i + k]) k++;
            if (j + z[j] < i + z[i]) j = i;
        }
        z[0] = n;
        return z;
    }

    std::vector<int> z_algorithm(const std::string& s) {
        int n = int(s.size());
        std::vector<int> s2(n);
        for (int i = 0; i < n; i++) {
            s2[i] = s[i];
        }
        return z_algorithm(s2);
    }

}  // namespace atcoder

#endif  // ATCODER_STRING_HPP

using namespace atcoder;

int main() {
    init();

    int n; cin >> n;
    string s; cin >> s;
    int ans = 0;
    FOR(i, 0, n) {
        VI a = z_algorithm(s.substr(i));
        FOR(j, i + 1, n)chmax(ans, min(a[j - i], j - i));
    }
    print(ans);

    return 0;
}

Measured memory_bytes: 3728