#include <bits/stdc++.h>

using namespace std;

#define int long long
#define double long double
#define FOR(i, a, b) for(ll i = (a); i < (b); ++i)
#define FORR(i, a, b) for(ll i = (a); i > (b); --i)
#define REP(i, n) for(ll i = 0; i < (n); ++i)
#define REPR(i, n) for(ll i = n; i >= 0; i--)
#define FOREACH(x, a) for(auto &(x) : (a))
#define VECCIN(x)                                                              \
    for(auto &youso_ : (x)) cin >> youso_
#define bitcnt(x) __builtin_popcount(x)
#define lbit(x) __builtin_ffsll(x)
#define rbit(x) __builtin_clzll(x)
#define SZ(x) ((ll)(x).size())
#define fi first
#define se second
#define All(a) (a).begin(), (a).end()
#define rAll(a) (a).rbegin(), (a).rend()

template <typename T = long long> inline T IN() {
    T x;
    cin >> x;
    return (x);
}
inline void CIN() {}
template <class Head, class... Tail>
inline void CIN(Head &&head, Tail &&... tail) {
    cin >> head;
    CIN(move(tail)...);
}
#define CCIN(...)                                                              \
    char __VA_ARGS__;                                                          \
    CIN(__VA_ARGS__)
#define DCIN(...)                                                              \
    double __VA_ARGS__;                                                        \
    CIN(__VA_ARGS__)
#define LCIN(...)                                                              \
    ll __VA_ARGS__;                                                            \
    CIN(__VA_ARGS__)
#define SCIN(...)                                                              \
    string __VA_ARGS__;                                                        \
    CIN(__VA_ARGS__)
#define Yes(a) cout << (a ? "Yes" : "No") << "\n"
#define YES(a) cout << (a ? "YES" : "NO") << "\n"
#define Printv(v)                                                              \
    {                                                                          \
        FOREACH(x, v) { cout << x << " "; }                                    \
        cout << "\n";                                                          \
    }
template <typename T = string> inline void eputs(T s) {
    cout << s << "\n";
    exit(0);
}
template <typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val) {
    std::fill((T *)array, (T *)(array + N), val);
}

template <typename T> using PQG = priority_queue<T, vector<T>, greater<T>>;
template <typename T> using PQ = priority_queue<T>;

typedef long long ll;
typedef vector<ll> VL;
typedef vector<VL> VVL;
typedef pair<ll, ll> PL;
typedef vector<PL> VPL;
typedef vector<bool> VB;
typedef vector<double> VD;
typedef vector<string> VS;

const int INF = 1e9;
const int MOD = 1e9 + 7;
// const int MOD = 998244353;
const ll LINF = 1e18;
// const double PI = atan(1.0) * 4.0;
const ll dx[] = {1, 1, 0, -1, -1, -1, 0, 1};
const ll dy[] = {0, 1, 1, 1, 0, -1, -1, -1};
#define PI 3.141592653589793238

// Sparse Table
template <class MeetSemiLattice> struct SparseTable {
    vector<vector<MeetSemiLattice>> dat;
    vector<int> height;

    SparseTable() {}
    SparseTable(const vector<MeetSemiLattice> &vec) { init(vec); }
    void init(const vector<MeetSemiLattice> &vec) {
        int n = (int)vec.size(), h = 0;
        while((1 << h) < n) ++h;
        dat.assign(h, vector<MeetSemiLattice>(1 << h));
        height.assign(n + 1, 0);
        for(int i = 2; i <= n; i++) height[i] = height[i >> 1] + 1;
        for(int i = 0; i < n; ++i) dat[0][i] = vec[i];
        for(int i = 1; i < h; ++i)
            for(int j = 0; j < n; ++j)
                dat[i][j] = min(dat[i - 1][j], dat[i - 1][min(j + (1 << (i - 1)), n - 1)]);
    }

    MeetSemiLattice get(int a, int b) {
        return min(dat[height[b - a]][a], dat[height[b - a]][b - (1 << height[b - a])]);
    }
};

// NlogN
struct SuffixArray {
    vector<int> SA;
    string s;

    SuffixArray(const string &str) { Build_SA(str); }

    void Build_SA(const string &str) {
        s = str;
        SA.resize(s.size());
        iota(begin(SA), end(SA), 0);
        sort(begin(SA), end(SA), [&](const int &a, const int &b) {
            if(s[a] == s[b]) return (a > b);
            return (s[a] < s[b]);
        });
        vector<int> classes(s.size()), c(s.size()), cnt(s.size());
        for(int i = 0; i < s.size(); i++) {
            c[i] = s[i];
        }
        for(int len = 1; len < s.size(); len <<= 1) {
            for(int i = 0; i < s.size(); i++) {
                if(i > 0 && c[SA[i - 1]] == c[SA[i]] && SA[i - 1] + len < s.size() && c[SA[i - 1] + len / 2] == c[SA[i] + len / 2]) {
                    classes[SA[i]] = classes[SA[i - 1]];
                } else {
                    classes[SA[i]] = i;
                }
            }
            iota(begin(cnt), end(cnt), 0);
            copy(begin(SA), end(SA), begin(c));
            for(int i = 0; i < s.size(); i++) {
                int s1 = c[i] - len;
                if(s1 >= 0) SA[cnt[classes[s1]]++] = s1;
            }
            classes.swap(c);
        }
        SA.insert(SA.begin(), s.size());
    }

    int operator[](int k) const { return (SA[k]); }

    int size() const { return (s.size()); }

    bool lt_substr(string &t, int si = 0, int ti = 0) {
        int sn = s.size(), tn = t.size();
        while(si < sn && ti < tn) {
            if(s[si] < t[ti]) return (true);
            if(s[si] > t[ti]) return (false);
            ++si, ++ti;
        }
        return (si >= sn && ti < tn);
    }

    int lower_bound(string &t) {
        int low = -1, high = SA.size();
        while(high - low > 1) {
            int mid = (low + high) >> 1;
            if(lt_substr(t, SA[mid]))
                low = mid;
            else
                high = mid;
        }
        return (high);
    }

    pair<int, int> lower_upper_bound(string &t) {
        int idx = lower_bound(t);
        int low = idx - 1, high = SA.size();
        t.back()++;
        while(high - low > 1) {
            int mid = (low + high) >> 1;
            if(lt_substr(t, SA[mid]))
                low = mid;
            else
                high = mid;
        }
        t.back()--;
        return (make_pair(idx, high));
    }

    void output() {
        for(int i = 0; i < size(); i++) {
            cout << i << ": " << s.substr(SA[i]) << endl;
        }
    }
};

struct LCP {
    vector<int> lcp, rank;
    SparseTable<int> st;

    LCP(SuffixArray &SA) { Build_LCP(SA); }

    int operator[](int k) const { return (lcp[k]); }

    int size() const { return (lcp.size()); }

    void Build_LCP(SuffixArray &SA) {
        string &s = SA.s;
        ll n = s.size();
        rank.resize(n + 1);
        for(int i = 0; i <= n; ++i) rank[SA[i]] = i;
        lcp.resize(n + 1);
        lcp[0] = 0;
        int cur = 0;
        for(int i = 0; i < n; ++i) {
            int pi = SA[rank[i] - 1];
            if(cur > 0) --cur;
            for(; pi + cur < n && i + cur < n; ++cur) {
                if(s[pi + cur] != s[i + cur]) break;
            }
            lcp[rank[i] - 1] = cur;
        }
        st.init(lcp);
    }

    // calc lcp
    int getLCP(int a, int b) { // lcp of str.sutstr(a) and str.substr(b)
        return st.get(min(rank[a], rank[b]), max(rank[a], rank[b]));
    }
};

signed main() {
    LCIN(N);
    SCIN(S);

    // Suffix Array 構築
    SuffixArray SA(S);
    LCP lcp(SA);

    // 全探索
    int res = 0;
    for(int i = 0; i < N; ++i) {
        for(int j = i + 1; j < N; ++j) {
            int val = lcp.getLCP(i, j);
            val = min(val, j - i);
            res = max(res, val);
        }
    }
    cout << res << endl;
}

Measured memory_bytes: 1408