#include <bits/stdc++.h>

#define st first
#define nd second
#define pb push_back
#define rep(i, a, b) for(int i = (a); i < (b); ++i)
#define sci(x) int x; cin >> x;
#define scvi(v, n) vector<int> v(n); rep(i, 0, n) cin >> v[i];

using namespace std;

typedef long long ll;
typedef pair<int, int> ii;
typedef vector<int> vi;

unordered_map<string, int> occ;


int main() {
    ios_base::sync_with_stdio(false); cin.tie(0);

    sci(n);
    string s;
    cin >> s;
    string r = s;
    reverse(r.begin(), r.end());

    string rr = "";
    rep(i, 0, n / 2 + 1) {
        rr += r[i];
        // cout << rr << '\n';
        occ[rr] = 1;
    }
    // cout << '\n';
    string s1 = s.substr(n - 1, 1);
    string s2 = s.substr(n - 2, 1);
    // cout << s1 << ' ' << s2 << '\n';


    // if(occ[ss] == 1) max_lght = i;
    
    int max_lght = 0;

    for(int i = 0; i <= n / 2; i++) {
        // cout << s1 << '\n';
        if(occ[s1] == 1) max_lght = 2 * i + 1;
        s1 = s[n - 2 * i - 3] + (s[n - 2 * i - 2] + s1.substr(0, s1.size() - 1));
    }
    // cout << '\n';
    for(int i = 1; i <= n / 2; i++) {
        // cout << s2 << '\n';
        if(occ[s2] == 1) max_lght = 2 * i;
        s2 = s[n - 2 * i - 2] + (s[n - 2 * i - 1] + s2.substr(0, s2.size() - 1));
    }
    cout << n - max_lght << '\n';

    return 0;
}