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

using namespace std;

string str;
string rev;
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;
    
    rev = str;
    reverse(rev.begin(), rev.end());

    int maxim = 0;

    for (int i = 0; i < n; i++) {
        int result = 0;
        int index = n - 1;

        while (index >= 0 && str[index] == rev[(index + i) % n]) {
            result++;
            index--;
        }

        maxim = max(result, maxim);
    }

    cout << n - maxim << endl;

}