#include <bits/stdc++.h>
// #include <boost/multiprecision/cpp_int.hpp>
// using i128 = boost::multiprecision::int128_t;
#define _GLIBCXX_DEBUG
using namespace std;
using ll = long long;
using ld = long double;
using V = vector<int>;
using Vll = vector<ll>;
using Vld = vector<ld>;
using Vbo = vector<bool>;
using VV = vector<V>;
using VVll = vector<Vll>;
using VVld = vector<Vld>;
using VVbo = vector<Vbo>;
using VVV = vector<VV>;
using VVVll = vector<VVll>;
using P = pair<int, int>;
using Pll = pair<ll, ll>;
using Pld = pair<ld, ld>;
#define rep2(i, m, n) for (int i = (m); i < (n); ++i)
#define drep2(i, m, n) for (int i = (m)-1; i >= (n); --i)
#define rep(i, n) rep2(i, 0, n)
#define drep(i, n) drep2(i, n, 0)
#define all(a) (a).begin(), (a).end()
struct fast_ios { fast_ios(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
template<typename T> inline int sz(T &x) { return x.size(); }
template<typename T> inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; }
template<typename T> inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; }
template<typename T1, typename T2> istream &operator>>(istream &is, pair<T1, T2> &p) { is >> p.first >> p.second; return is; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p) { os << '(' << p.first << ", " << p.second << ')'; return os; }
template<typename T> istream &operator>>(istream &is, vector<T> &v) { for (auto &e : v) is >> e; return is; }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &v) { for (auto &e : v) os << e << ' '; return os; }
template<typename T> inline int count_between(vector<T> &a, T l, T r) { return lower_bound(all(a), r) - lower_bound(all(a), l); } // [l, r)
inline int fLog2(const int x) { return 31-__builtin_clz(x); } // floor(log2(x))
inline int fLog2(const ll x) { return 63-__builtin_clzll(x); }
inline int cLog2(const int x) { return (x == 1) ? 0 : 32-__builtin_clz(x-1); } // ceil(log2(x))
inline int cLog2(const ll x) { return (x == 1) ? 0 : 64-__builtin_clzll(x-1); }
inline int popcount(const int x) { return __builtin_popcount(x); }
inline int popcount(const ll x) { return __builtin_popcountll(x); }
const int INF  = 1<<30;
const ll INFll = 1ll<<62;
const ld EPS   = 1e-10;
const ld PI    = acos(-1.0);
// const int MOD  = int(1e9)+7;
// const int MOD  = 998244353;


struct RollingHash {
  using ui64 = uint64_t;
  using ui128 = __uint128_t;
  static const ui64 mod = (1ull<<61) - 1;
  vector<ui64> hash, power;
  ui64 base;

  static inline ui64 add(ui64 a, ui64 b) { if ((a += b) >= mod) a -= mod; return a; }
  static inline ui64 mul(ui64 a, ui64 b) { ui128 c = ui128(a)*b; return add(c>>61, c&mod); }
  static inline ui64 generate_base() {
    mt19937_64 mt(chrono::steady_clock::now().time_since_epoch().count());
    uniform_int_distribution<ui64> rand(2, mod-2);
    return rand(mt);
  }

  template<typename T>
  RollingHash(const T &s) {
    base = generate_base();
    int n = s.size();
    hash.assign(n+1, 0);
    power.assign(n+1, 1);
    rep(i, n) {
      power[i+1] = mul(power[i], base);
      hash[i+1] = add(mul(hash[i], base), s[i]);
    }
  }

  ui64 query(int l, int r) const { return add(hash[r], mod - mul(hash[l], power[r-l])); }
  ui64 combine(ui64 h1, ui64 h2, size_t h2len) const { return add(mul(h1, power[h2len]), h2); }

  int lcp(int l1, int r1, int l2, int r2) const {
    int len = min(r1-l1, r2-l2);
    int ok = 0, ng = len+1;
    while (ng-ok > 1) {
      int md = (ok+ng)>>1;
      if (query(l1, l1+md) == query(l2, l2+md)) ok = md;
      else ng = md;
    }
    return ok;
  }
};


int main() {
    int n; cin >> n;
    string s; cin >> s;
    RollingHash rh(s);

    int ans = 0;
    rep(i, n) rep2(j, i+1, n) {
      int lcp = rh.lcp(i, n, j, n);
      chmin(lcp, j-i);
      chmax(ans, lcp);
    }
    cout << ans << endl;
}



Measured memory_bytes: 3752