#include <bits/stdc++.h>
#include <boost/multiprecision/cpp_int.hpp>
using namespace std;

//#define int long long
using bll = boost::multiprecision::cpp_int;
using ll = long long;
//constexpr int INF = 1e9;//INT_MAX=(1<<31)-1=2147483647
constexpr ll INF = (ll)1e18;//(1LL<<63)-1=9223372036854775807
constexpr ll MOD = (ll)1e9 + 7;
constexpr double EPS = 1e-9;
constexpr int dx[4]={1,0,-1,0};
constexpr int dy[4]={0,1,0,-1};
#ifdef LOCAL_ENV
	#define debug(var) std::cout<<#var" = "<<var<<std::endl
#else
	#define debug(var)
#endif
#define p(var) std::cout<<var<<std::endl
#define PI (acos(-1))
#define rep(i, n)   for(ll i=0, i##_length=(n); i< i##_length; ++i)
#define repeq(i, n) for(ll i=1, i##_length=(n); i<=i##_length; ++i)
#define all(v) (v).begin(), (v).end()
#define uniq(v) (v).erase(unique((v).begin(), (v).end()), (v).end());
template<typename T> inline void pv(vector<T> v) { for(ll i=0, N=v.size()-1; i<=N; i++) if(i!=N) cout << v[i] << ' '; else cout << v[i] << endl; }
template<typename T> inline T power(T x, T n){ return n ? power(x*x%MOD,n/2)*(n%2?x:1)%MOD : 1; }
template<typename T> inline T gcd(T a, T b) { return b ? gcd(b,a%b) : a; }
template<typename T> inline T lcm(T a, T b) { return a / gcd(a,  b) * b; }
template<typename T1, typename T2>inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }
template<typename T1, typename T2>inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }
template<typename T1, typename T2> ostream& operator<<(ostream& s, const pair<T1, T2>& p) {return s << "(" << p.first << ", " << p.second << ")";}
template<typename T> ostream& operator<<(ostream& s, const vector<T>& v) {
	for (int i = 0, len = v.size(); i < len; ++i){
		s << v[i]; if (i < len - 1) s << "\t";
	}
	return s;
}
template<typename T> ostream& operator<<(ostream& s, const vector< vector<T> >& vv) {
	for (int i = 0, len = vv.size(); i < len; ++i){
		s << vv[i] << endl;
	}
	return s;
}
template<typename T1, typename T2> ostream& operator<<(ostream& s, const map<T1, T2>& m) {
	s << "{" << endl;
	for (typeof(m.begin()) itr = m.begin(); itr != m.end(); ++itr){
		s << "\t" << (*itr).first << " : " << (*itr).second << endl;
	}
	s << "}" << endl;
	return s;
}

/*-----8<-----8<-----*/

// 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])]);
	}
};

/*
SuffixArray(str):= 文字列 str の接尾辞配列を構築する。
lower_upper_bound(t):= 文字列 t を含む接尾辞のindexの下限と上限(半開区間)を返す。
空文字列が入っていない実装なので注意すること。
*/
class SuffixArray {
public:
	vector< int > SA;
	const string s;

	SuffixArray(const string &str) : s(str) {
		int sz = s.size();
		SA.resize(sz);
		iota(begin(SA), end(SA), 0);
		sort(begin(SA), end(SA), [&](int a, int b) {
			return s[a] == s[b] ? a > b : s[a] < s[b];
		});
		vector< int > classes(sz), c(s.begin(), s.end()), cnt(sz);
		for(int len = 1; len < sz; len <<= 1) {
			for(int i = 0; i < sz; i++) {
				if(i > 0 && c[SA[i - 1]] == c[SA[i]] && SA[i - 1] + len < sz && 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 < sz; i++) {
				int s1 = c[i] - len;
				if(s1 >= 0) SA[cnt[classes[s1]]++] = s1;
			}
			classes.swap(c);
		}
	}

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

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

	bool lt_substr(const string &t, int si = 0, int ti = 0) {
		int sn = (int) s.size(), tn = (int) 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(const string &t) {
		int low = -1, high = (int) SA.size();
		while(high - low > 1) {
			int mid = (low + high) / 2;
			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 = (int) SA.size();
		t.back()++;
		while(high - low > 1) {
			int mid = (low + high) / 2;
			if(lt_substr(t, SA[mid])) low = mid;
			else high = mid;
		}
		t.back()--;
		return {idx, high};
	}

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

/*
LongestCommonPrefixArray(SA):= 接尾辞配列 SA をもとに高さ配列を構築する。
高さ配列＝接尾辞配列 SA における隣同士の接尾辞で、先頭何文字が共通しているかを表す配列
*/
class LongestCommonPrefixArray {
public:
	const SuffixArray &SA;
	vector< int > LCP, rank;
	SparseTable< int > st;

	LongestCommonPrefixArray(const SuffixArray &SA) : SA(SA), LCP(SA.size()) {
		int sz = SA.size();
		rank.resize(sz);
		for(int i = 0; i < sz; i++) {
			rank[SA[i]] = i;
		}
		for(int i = 0, h = 0; i < sz; i++) {
			if(rank[i] + 1 < sz) {
				for(int j = SA[rank[i] + 1]; max(i, j) + h < sz && SA.s[i + h] == SA.s[j + h]; ++h);
				LCP[rank[i] + 1] = h;
				if(h > 0) --h;
			}
		}
		st.init(LCP);
		debug(LCP);
		debug(rank);
	}

	// lcp of str.sutstr(a) and str.substr(b)
	// 文字strのa文字目からとb文字目からで何文字共通しているか
    int getLCP(int a, int b) {
        return st.get(min(rank[a], rank[b]) + 1, max(rank[a], rank[b]) + 1);
    }

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

	size_t size() const {
		return LCP.size();
	}

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

signed main() {
	ll N;
	string S;
	cin>>N>>S;

	SuffixArray sa(S);
	LongestCommonPrefixArray lcpa(sa);

	ll ans=0;
	for(ll i=0;i<N-1;i++){
		for(ll j=i+1;j<N;j++){
			ll t=lcpa.getLCP(i,j);
			if(t>j-i)t=j-i;
			debug(i);debug(j);debug(t);debug("-----------");
			chmax(ans,t);
		}
	}
	cout<<ans<<endl;
	return 0;
}


Measured memory_bytes: 768