#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

using ull = unsigned long long;

int main() {
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    string s;
    cin >> s;
    reverse(s.begin(), s.end());
    ull a = 0, b = 0;
    const ull M = 31415926535;
    ull Mh = 1;
    int m = 0;
    for(int i = 0; i < N; i++){
        int x = s[i] - 'a';
        a += Mh * x;
        Mh *= M;
        b *= M;
        b += x;
        //cerr << a << " " << b << "\n";
        if(a == b) {
            m = max(m, i);
        }
    }
    cout << N - m - 1 <<"\n";
}

/*int main() {
    string s;
    cin >> s;
    vector<int> tomb(s.size()+1);
    s[0] = -1;
    for(int i = 0; i < N; i++) {
        int j = tomb[i];
        while(j >= 0 && s[j] != s[i]) {
            j = tomb[i];
        }
        s[i+1] = j + 1;
    }
    int o = 0;
    for(int i = 0; i < N; i++) {
        if (i > o || s[i] != s[o - i]) {

        }
    }
}*/

/*const int MAXL = 4e5+5;

int d[MAXL];

int main()
{
    ios_base::sync_with_stdio(0);
    int N;
    cin >> N;
    string s;
    cin >> s;

    int maxc = N-1;
    int c = N-1; /// center
    d[N-1] = N;
    /// PT
    for(int i = N-2; i >= 0; i--) {
        while(2*c-i >= N && s[i] != s[2*c-i]) {
            if (2*c - i >= N) {
                maxc = c;
            }
        }
    }

    return 0;
}
*/