#include<bits/stdc++.h>
#define ll                  long long
#define dl                 double
#define pb                push_back
#define F                  first
#define S                  second
#define endl              "\n"
#define rep(i,a,b)       for(i=a;i<b;i++)
#define all(v)             v.begin(),v.end()
#define allr(v)            v.rbegin(),v.rend()
#define mod              1000000007
#define CIN(V,s,n)      for(int i=s;i<n;i++){cin >> V[i];}
#define COUT(V,s,n)   {for(int i=s;i<n;i++){cout <<  V[i] << " "  ;} cout << endl;}
#define fast               ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define CLEAR(V);      for(ll i=0;i<V.size();i++) V[i] = 0;
#define N                  100000LL
#define tmod            998244353
using namespace std;

bool sBs(const pair<int,int> &a,const pair<int,int> &b)
{   return (a.second < b.second);   }

ll SUMD(ll n);
ll BS(vector<ll> &PS,ll s,ll e,ll ser);
ll MI(ll a, ll m);
bool P[N + 1];
void Sieve(int n=N);
ll Powb(ll b,ll n);

ll maxa=0;

void cLPS(string &s)
{
    int n=s.size(),i,j;
    vector<ll> LPS(n);
    for(i=1,j=0;i<n;)
    {
        if(s[i]==s[j])
        {
            j++; LPS[i] = j;i++;

            if(LPS[i-1] <= i/2)  maxa = max(maxa,LPS[i-1]);
            else
            {
                if(i%(i-LPS[i-1])==0) {
                    ll temp = ((i/2)/(i-LPS[i-1]))*(i-LPS[i-1]);
                    maxa = max(maxa,temp);
                }
            }
        }
        else
        {
            if(j) j = LPS[j-1];
            else i++;
        }
        //cout << " y " << i << " y " << j;
    }
    LPS.clear();
}



int main()
{
//fast;
ll q=1;
//cin >> q;
while(q--)
{
    ll n,m,k,i,j,l,r,a,b,c=0,g,counter=0,u,v,d,e,x,w,y;//flag=1;
    //n=m=i=j=l=r=a=t=b=c=u=v=w=p=x=y=0;
    cin >> n;
    string s;
    cin >> s;



    for(j=0;j<n;j++)
        {
            string s1 = s.substr(j,n-j);
            cLPS(s1);
        }

    cout << maxa;

}
    return 0;
}

//*****************************************************************************************************************************************

ll Powb(ll b,ll n)
{
    if(n==0) return 1LL;
    if(n==1) return b;
    ll temp = Powb(b,n/2);
    if(n%2==0){return (temp*temp)%mod;}
    else{return (b*((temp*temp)%mod))%mod;}
}

ll SUMD(ll n)
{   ll sum=0;
    while(n>0){sum += n%10;n = n/10;}
    return sum;

}
ll BS(vector<ll> &PS,ll s,ll e,ll ser)
{
    if(s>e)
        return s;
    ll mid = (s+e)/2;
    if(PS[mid]==ser)
    {
        return mid;
    }
    else if(PS[mid] > ser)
    {
        return BS(PS,s,mid-1,ser);
    }
    else
        return BS(PS,mid+1,e,ser);
}
ll MI(ll a, ll m)
{
    ll m0 = m;
    ll y = 0, x = 1;
    if (m == 1)
      return 0;
    while (a > 1)
    {
        ll q = a / m;
        ll t = m;
        m = a % m, a = t;
        t = y;
        y = x - q * y;
        x = t;
    }
    if (x < 0)
       x += m0;
    return x;
}

void Sieve(int n)
{
    memset(P,true,sizeof(P));
    P[0] = false;
    P[1]= false;
    for(ll i=2;i*i<=n;i++)
    {
        if(P[i])
        {
            for(ll j=i*i;j<=n;j+=i)
            {
                P[j]=false;
            }
        }
    }

}


Measured memory_bytes: 384