#include <bits/stdc++.h>
#define pb push_back
#define all(c) c.begin(),c.end()
using namespace std;
typedef long long ll;
const ll INF64 = 1e18 + 1337;
const int INF32 = 1e9 + 228;
const int MOD = 1e9 + 7;
int main()
{
    ios_base::sync_with_stdio(0);
#ifndef __WIN32
  ifstream cin("input.txt");
  ofstream cout("output.txt");
#endif
    cin.tie(0);cout.tie(0);

    int n;
    cin >> n;
    vector<int> a(n);
    for(auto& it : a) cin >> it;
    vector<int> p(n, 0);
    for(int i = 1; i < n; i++)
    {
        int j = p[i - 1];
        while(j > 0 && a[i] != a[j])
        {
            j = p[j - 1];
        }
        if(a[i] == a[j]) j++;
        p[i] = j;
    }
    for(int i = n - 1; i >= 0; i--)
    {
        if(p[i] == 1)
        {
            cout << ((((p[n - 1] - 1) % i) == 0) ? i : n - 1);
            return 0;
        }
    }

#ifndef __WIN32
  cin.close();
  cout.close();
#endif
    return 0;
}