Where Am I?

// NgJaBach: Forever Meadow <3

#include<bits/stdc++.h>

using namespace std;
typedef long long int ll;
typedef unsigned long long ull;
#define pb push_back
#define pob pop_back
#define mp make_pair
#define upb upper_bound
#define lwb lower_bound
#define bend(a) a.begin(),a.end()
#define rev(x) reverse(bend(x))
#define mset(a) memset(a, 0, sizeof(a))
#define fi first
#define se second
#define gcd __gcd
#define getl(s) getline(cin, s);
#define setpre(x) fixed << setprecision(x)
#define endl '\n'
const int N=200050,M=1000000007;
const ll INF=1e18+7;
int main(){
    ios_base::sync_with_stdio(NULL); cin.tie(nullptr); cout.tie(nullptr);
    freopen("whereami.in","r",stdin);
    freopen("whereami.out","w",stdout);
    int n,L,R,mid,ans;
    set<string>ex;
    string s,str;
    cin>>n;
    cin>>s;
    ans=n;
    L=1; R=n;
    while(L<=R){
        mid=(L+R)/2;
        ex.clear();
        for(int i=mid-1;i<n;++i){
            str.clear();
            for(int j=i-mid+1;j<=i;++j){
                str.pb(s[j]);
            }
            ex.insert(str);
        }
        if(ex.size()!=(n-mid+1)) L=mid+1;
        else{
            R=mid-1;
            ans=min(ans,mid);
        }
    }
    cout<<ans;
    return 0;
}
/*
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INPUT:                            |
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OUTPUT:                           |
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*/