#include<bits/stdc++.h>
using namespace std;

#define endl '\n'
#define ALL(a)  (a).begin(),(a).end()
#define ALLR(a)  (a).rbegin(),(a).rend()
#define spa << " " <<
#define lfs 
#define test cout<<"test"<<endl;
#define fi first
#define se second
#define MP make_pair
#define PB push_back
#define EB emplace_back
#define rep(i,n,m) for(ll i = n; i < (ll)(m); i++)
#define rrep(i,n,m) for(ll i = m - 1; i >= (ll)(n); i--)
using ll = long long;
using ld = long double;
const ll MOD = 1e9+7;
//const ll MOD = 998244353;
const ll INF = 1e18;
using P = pair<ll, ll>;
template<typename T>
void chmin(T &a,T b){if(a>b)a=b;}
template<typename T>
void chmax(T &a,T b){if(a<b)a=b;}
void pmod(ll &a,ll b){a=(a+b)%MOD;}
void pmod(ll &a,ll b,ll c){a=(b+c)%MOD;}
void qmod(ll &a,ll b){a=(a*b)%MOD;}
void qmod(ll &a,ll b,ll c){a=(b*c)%MOD;}
ll median(ll a,ll b, ll c){return a+b+c-max({a,b,c})-min({a,b,c});}
void ans1(bool x){if(x) cout<<"Yes"<<endl;else cout<<"No"<<endl;}
void ans2(bool x){if(x) cout<<"YES"<<endl;else cout<<"NO"<<endl;}
void ans3(bool x){if(x) cout<<"Yay!"<<endl;else cout<<":("<<endl;}
template<typename T1,typename T2>
void ans(bool x,T1 y,T2 z){if(x)cout<<y<<endl;else cout<<z<<endl;}  
template<typename T>
void debug(vector<vector<T>>&v,ll h,ll w){for(ll i=0;i<h;i++)
{cout<<v[i][0];for(ll j=1;j<w;j++)cout spa v[i][j];cout<<endl;}};
void debug(vector<string>&v,ll h,ll w){for(ll i=0;i<h;i++)
{for(ll j=0;j<w;j++)cout<<v[i][j];cout<<endl;}};
template<typename T>
void debug(vector<T>&v,ll n){if(n!=0)cout<<v[0];
for(ll i=1;i<n;i++)cout spa v[i];cout<<endl;};
template<typename T>
vector<vector<T>>vec(ll x, ll y, T w){
  vector<vector<T>>v(x,vector<T>(y,w));return v;}
ll gcd(ll x,ll y){ll r;while(y!=0&&(r=x%y)!=0){x=y;y=r;}return y==0?x:y;}
vector<ll>dx={1,0,-1,0,1,1,-1,-1};
vector<ll>dy={0,1,0,-1,1,-1,1,-1};
template<typename T>
vector<T> make_v(size_t a,T b){return vector<T>(a,b);}
template<typename... Ts>
auto make_v(size_t a,Ts... ts){
  return vector<decltype(make_v(ts...))>(a,make_v(ts...));
}
struct SuffixArray{
  ll size;
  string str;
  vector<ll>data;
  SuffixArray(string S):size(S.size()),str(S){
    str += '$';
    vector<ll>input(str.size());
    for(ll i=0;i<str.size();i++)input[i] = str[i];
    data = induced_sort(input, 200);
    data.erase(data.begin()); data.push_back(size);
    str.pop_back();
  }
  vector<ll> induced_sort(vector<ll>t, ll kind){
    ll sz = t.size();
    vector<bool>ls(sz);//trueはL型,falseはS型
    for(ll i = sz-1;i>=0;i--){
      if(i==sz-1)ls[i] = false;
      else{
        if(t[i]!=t[i+1])ls[i] = (t[i] > t[i+1]);
        else ls[i] = ls[i+1];
      }
    }
    vector<ll>cnt(kind);
    for(ll i=0;i<sz;i++)cnt[t[i]]++;
    vector<P>lr(kind,MP(-1,-1));
    for(ll i=1;i<kind;i++){
      if(cnt[i]==0)lr[i] = lr[i-1];
      else lr[i] = make_pair(lr[i-1].se + 1, lr[i-1].se + cnt[i]);
    }
    vector<ll>lmsidx,ret(sz,-1);
    for(ll i=0;i<sz-1;i++){
      if(ls[i]&&!ls[i+1]){
        ret[lr[t[i+1]].fi+cnt[t[i+1]]-1]=i+1;
        cnt[t[i+1]]--;
        lmsidx.push_back(i+1);
      }
    }
    fill(ALL(cnt),0);
    for(ll i=0;i<sz;i++){
      if(ret[i]>=1&&ls[ret[i]-1]){
        ret[lr[t[ret[i]-1]].fi+cnt[t[ret[i]-1]]]=ret[i]-1;
        cnt[t[ret[i]-1]]++;
        if(i!=0&&!ls[ret[i]])ret[i]=-1;
      }
    }
    fill(ALL(cnt),0);
    for(ll i=sz-1;i>=1;i--){
      if(ret[i]>=1&&!ls[ret[i]-1]){
        ret[lr[t[ret[i]-1]].se-cnt[t[ret[i]-1]]]=ret[i]-1;
        cnt[t[ret[i]-1]]++;
      }
    }
    vector<ll>rev_lmsidx(sz,-1),lmsinput(lmsidx.size(),-1);
    for(ll i=0;i<lmsidx.size();i++)rev_lmsidx[lmsidx[i]] = i;
    ll kindnum=1; 
    lmsinput[rev_lmsidx[ret[0]]] = 1;
    vector<ll>comp(t.begin()+ret[0],t.end());
    for(ll i=1;i<sz;i++){
      if(ret[i]>=1&&ls[ret[i]-1]&&!ls[ret[i]]){
        vector<ll>tmp(t.begin()+ret[i],t.begin()+lmsidx[rev_lmsidx[ret[i]]+1]+1); 
        if(comp != tmp){
          kindnum++;
          comp = tmp;
        }
        lmsinput[rev_lmsidx[ret[i]]] = kindnum;
      }
    }
    vector<ll>output;
    if(kindnum==lmsidx.size()){
      output.assign(kindnum,-1);
      for(ll i=0;i<lmsinput.size();i++)output[lmsinput[i]-1]=i;
    }
    else output = induced_sort(lmsinput,kindnum+1);
    
    fill(ALL(cnt),0), fill(ALL(ret),-1);
    for(ll i=output.size()-1;i>=0;i--){
      ll tmp=lmsidx[output[i]];
      ret[lr[t[tmp]].se - cnt[t[tmp]]]=tmp;
      cnt[t[tmp]]++;
    }
    fill(ALL(cnt),0);
    for(ll i=0;i<sz;i++){
      if(ret[i]>=1&&ls[ret[i]-1]){
        ret[lr[t[ret[i]-1]].fi+cnt[t[ret[i]-1]]]=ret[i]-1;
        cnt[t[ret[i]-1]]++;
        if(i!=0&&!ls[ret[i]])ret[i]=-1;
      }
    }
    fill(ALL(cnt),0);
    for(ll i=sz-1;i>=1;i--){
      if(ret[i]>=1&&!ls[ret[i]-1]){
        ret[lr[t[ret[i]-1]].se-cnt[t[ret[i]-1]]]=ret[i]-1;
        cnt[t[ret[i]-1]]++;
      }
    }
    return ret;
  }
  ll operator[](ll x) const {
    return data[x];
  }
  ll lower_bound(string x){
    ll le=-1,ri=str.size();
    while(ri-le>=2){
      ll mid=(le+ri)/2;
      ll cnt=0;
      while(cnt<x.size()&&data[mid]+cnt<str.size()
        &&x[cnt]==str[data[mid]+cnt])cnt++;
      if(cnt==x.size())ri=mid;
      else if(data[mid]+cnt==str.size())le=mid;
      else if(x[cnt]<=str[data[mid]+cnt])ri=mid;
      else le=mid;
    }
    return ri;
  }
  ll upper_bound(string x){
    x.back()++;
    return lower_bound(x);
  }
  vector<ll> LCP(){
    vector<ll>lcp(size),rank(size);
    for(ll i=0;i<size;i++){
      rank[data[i]] = i;
    }
    for(ll i=0,h=0;i<size;i++){
      if(rank[i] + 1 < size){
        for(ll j=data[rank[i]+1];max(i,j)+h<size
          &&str[i+h]==str[j+h];h++);
          lcp[rank[i]+1] = h;
        if(h>0) h--;
      }
    }
    return lcp;
  }
};
template< typename T >
struct SparseTable {
  vector< vector< T > > st;
  vector< int > lookup;

  SparseTable(const vector< T > &v) {
    int b = 0;
    while((1 << b) <= v.size()) ++b;
    st.assign(b, vector< T >(1 << b));
    for(int i = 0; i < v.size(); i++) {
      st[0][i] = v[i];
    }
    for(int i = 1; i < b; i++) {
      for(int j = 0; j + (1 << i) <= (1 << b); j++) {
        st[i][j] = min(st[i - 1][j], st[i - 1][j + (1 << (i - 1))]);
      }
    }
    lookup.resize(v.size() + 1);
    for(int i = 2; i < lookup.size(); i++) {
      lookup[i] = lookup[i >> 1] + 1;
    }
  }

  inline T rmq(int l, int r) {
    int b = lookup[r - l];
    return min(st[b][l], st[b][r - (1 << b)]);
  }
};

int main(){
  cin.tie(nullptr);
  ios_base::sync_with_stdio(false);
  //cout<<fixed<<setprecision(10);
  ll res=0,buf=0;
  bool judge = true;
  ll n;cin>>n;
  string s;cin>>s;
  SuffixArray sa(s);
  auto v=sa.LCP();
  SparseTable<ll>segtree(v);
  vector<ll>rank(s.size());
  rep(i,0,s.size())rank[sa[i]]=i+1;
  rep(i,0,s.size())rep(j,i+1,s.size()){
    ll l=min(rank[i],rank[j]),r=max(rank[i],rank[j]);
    chmax(res,min(j-i,segtree.rmq(l,r)));
  }
  //debug(v,v.size());
  cout<<res<<endl;
  return 0;
}

Measured memory_bytes: 1356