#include <iostream>
//#include <algorithm>
//#include <string>
using namespace std;

int main(){
    int n;
    string s, p = "";
    cin >> n;
    cin >> s;

    for (const char& c : s){
        p = c + p;
    }

    //cout<<s<<endl<<p<<endl;

    int b[n + 1];
    b[0] = -1;
    int i = 0, j = -1;

    while (i < n){
        while (j >= 0 && p[i] != p[j]) j = b[j];
        i++;
        j++;
        b[i] = j;
    }

    i = 0;
    j = 0;
    int len = 0;
    while (i < n) {
        while (j >= 0 && s[i] != p[j]) j = b[j];
        i++;
        j++;
        //cout<<i<<", "<<j<<endl;
        if (j + i == n - 1){
            len = 2 * j + 1;
            break;
        }
        else if (j + i >= n){
            len = 2 * j;
            break;
        }
    }

    cout<< n - len<<endl;
}