#include <algorithm>
#include <cassert>
#include <cfloat>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <deque>
#include <iostream>
#include <iterator>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

#define FOR(i,k,n) for(int(i)=(k);(i)<(n);++(i))
#define rep(i,n) FOR(i,0,n)
#define all(v) begin(v),end(v)
#define debug(x) std::cerr<<#x<<": "<<x<<"\n"
#define debug2(x,y) std::cerr<<#x<<": "<<x<<", "<<#y<<": "<<y<<"\n"
#define debug3(x,y,z) std::cerr<<#x<<": "<<x<<", "<<#y<<": "<<y<<", "<<#z<<": "<<z<<"\n"

using ll=long long;
using vi=std::vector<int>;
using vvi=std::vector<vi>;
using vll=std::vector<ll>;
using vvll=std::vector<vll>;
template<typename T> using vvec=std::vector<std::vector<T>>;
template<typename T>
auto make_v(size_t sz){return std::vector<T>(sz);}
template<typename T,typename... Ts>
auto make_v(size_t sz,Ts...ts){return std::vector<decltype(make_v<T>(ts...))>(sz,make_v<T>(ts...));}
template<typename T>
void fill_v(T&var,const T&x){var=x;}
template<typename V,typename T>
void fill_v(V&v,const T&x){for(auto&& w:v){fill_v(w,x);}}

template<typename T> std::ostream& operator<<(std::ostream&s,const std::vector<T>&v){
  int sz=v.size();s<<"\n";rep(i,sz){s<<v[i];if(i<sz-1){s<<"\t";}}s<<"\n";return s;}
template<typename T> std::ostream& operator<<(std::ostream&s,const std::vector<std::vector<T>>&v){
  for(auto&& w:v){s<<w;}return s;}
template<typename T> std::ostream& operator<<(std::ostream&s,const std::deque<T>&v){
  int sz=v.size();s<<"\n";rep(i,sz){s<<v[i];if(i<sz-1){s<<"\t";}}s<<"\n";return s;}
template<typename T> std::ostream& operator<<(std::ostream&s,const std::deque<std::deque<T>>&v){
  for(auto&& w:v){s<<w;}return s;}
template<typename T> std::ostream& operator<<(std::ostream&s, const std::set<T>&v){
  s<<"\n";for(auto&& elm:v){s<<elm<<"\t";}s<<"\n";return s;}

inline void scan(int&a){scanf("%d",&a);}
inline void scan(ll&a){scanf("%lld",&a);}
inline void scan(char&a){scanf(" %c",&a);}
inline void scan(double&a){scanf("%lf",&a);}
inline void scan(std::string&s){char BUF[3000000];scanf(" %s",BUF);s=std::string(BUF);}
template<typename T>
inline void scan(std::vector<T>&v){for(auto&& sv:v){scan(sv);}}
template<typename First,typename...Args>
inline void scan(First&f,Args&...args){scan(f);scan(args...);}
inline void print(int a){printf("%d\n",a);}
inline void print(ll a){printf("%lld\n",a);}
inline void print(double a){printf("%.12f\n",a);}
inline void print(std::string s){std::cout<<s<<"\n";}

class RollingHash {
  using ll = long long;
private:
  std::vector<ll> data;
  ll base;
  std::vector<ll> mod;
  std::vector<std::vector<ll> > power_base;
  std::vector<std::vector<ll> > hash;

  void assign_base() {
    std::random_device rnd;
    std::mt19937 mt(rnd());
    base = mt() % (mod[0] - 3) + 2;
  }
  void assign_hash() {
    power_base.assign(data.size(), std::vector<ll>(mod.size(), 0));
    for (size_t i = 0; i < mod.size(); ++i) {
      power_base[0][i] = 1;
    }
    for (size_t i = 0; i < data.size() - 1; ++i) {
      for (size_t j = 0; j < mod.size(); ++j) {
        power_base[i+1][j] = power_base[i][j] * base % mod[j];
      }
    }
    hash.assign(data.size() + 1, std::vector<ll>(mod.size(), 0));
    for (size_t i = 0; i < data.size(); ++i) {
      for (size_t j = 0; j < mod.size(); ++j) {
        hash[i+1][j] = (hash[i][j] + data[i] * power_base[i][j]) % mod[j];
      }
    }
  }

public:
  RollingHash() {}
  RollingHash(std::vector<ll>& v) : data(v) {
    mod = {1000000007, 1000000009, 1000000021};
    assign_base();
    assign_hash();
  }
  RollingHash(std::vector<ll>& v, std::vector<ll>& m) : data(v), mod(m) {
    std::sort(std::begin(mod), std::end(mod));
    assign_base();
    assign_hash();
  }

  std::vector<int> include(std::vector<ll> data2) {
    std::vector<int> ret;
    if (data.size() < data2.size()) {
      return ret;
    }
    std::vector<ll> hash2(mod.size(), 0);
    for (size_t i = 0; i < data2.size(); ++i) {
      for (size_t j = 0; j < mod.size(); ++j) {
        hash2[j] = (hash2[j] + data2[i] * power_base[i][j]) % mod[j];
      }
    }
    for (size_t i = 0; i < data.size() - data2.size() + 1; ++i) {
      bool flag = true;
      for (size_t j = 0; j < mod.size(); ++j) {
        if (hash[i + data2.size()][j] != (hash[i][j] + hash2[j] * power_base[i][j]) % mod[j]) {
          flag = false;
          break;
        }
      }
      if (flag) {
        ret.push_back(i);
      }
    }
    return ret;
  }
  std::vector<std::vector<ll> > hash_list(int len) {
    size_t m = data.size() - len + 1;
    std::vector<std::vector<ll> > hash_list(m, std::vector<ll>(3, 0));
    for (size_t i = 0; i < m; ++i) {
      for (size_t j = 0; j < mod.size(); ++j) {
        hash_list[i][j] = (hash[i + len][j] - hash[i][j] + mod[j]) * power_base[m - 1 - i][j] % mod[j];
      }
    }
    return hash_list;
  }
};

using namespace std;

int main() {
  int n;
  scan(n);
  string s;
  scan(s);
  vll vs(n, 0);
  rep (i, n) {
    vs[i] = s[i] - '/';
  }
  RollingHash rh(vs);

  int ok = 0;
  int ng = n;
  while (ng - ok > 1) {
    int mid = (ok + ng) / 2;
    auto hl = rh.hash_list(mid);

    int m = hl.size();
    bool flag_ok = false;
    rep (i, m-1) {
      FOR (j, i + mid, m) {
        if (hl[i] == hl[j]) {
          ok = mid;
          flag_ok = true;
          break;
        }
      }
      if (flag_ok) {
        break;
      }
    }
    if (!flag_ok) {
      ng = mid;
    }
  }
  print(ok);

  return 0;
}


Measured memory_bytes: 3144