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

using namespace std;

string str;
string c;

bool isPalindrome()  {

    int div_point;
    string eleje;
    string vege;

    if ((c.length()) % 2 == 0) {
        div_point = c.length() / 2;
        eleje = c.substr(0, div_point);
        vege = c.substr(div_point);

    } else {
        div_point = c.length() / 2 + 1;
        eleje = c.substr(0, div_point);
        vege = c.substr(div_point - 1);
    }

    reverse(vege.begin(), vege.end());

    return (vege == eleje);
}

int main() {

    int n;
    cin >> n >> str;
    int div = n / 2;
    string str_to_find;
    string c;
    
    while (div != n) {
        str_to_find  = str.substr(div);
        reverse(str_to_find.begin(), str_to_find.end());

        c = str;
        size_t t;
        while (t = c.find(str_to_find), t != string::npos) {
            c = c.substr(t);

            if (isPalindrome()) {
                cout << n - c.length() << endl;
                return 0;
            }
            c = c.substr(1);
        }

        div++;
    }
}