#include <bits/stdc++.h>
using namespace std;
const int N = 1000010;
int n, ne[N];
char p[N];
int main() {
    cin >> n >> (p + 1);
    // 求模式串ne数组
    for (int i = 2, j = 0; i <= n; i++) {
        while (j && p[i] != p[j + 1]) j = ne[j];
        if (p[i] == p[j + 1]) j++;
        ne[i] = j;
    }
    printf("%d", n - ne[n]);
    return 0;
}