#include <bits/stdc++.h>
#define int long long
using namespace std;
const int MAXL = 1000000;
string t, p;
int nxt[MAXL + 5];
void getNxt(const string &s)
{
    nxt[0] = 0;
    for (int i = 1; i < s.length(); i++)
    {
        int j = nxt[i - 1];
        while (j != 0 && s[j] != s[i])
            j = nxt[j - 1];
        if (s[j] == s[i])
            j++;
        nxt[i] = j;
    }
}
int L;
string s;
signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> L;
    cin >> s;
    getNxt(s);
    cout << L - nxt[L - 1] << "\n";
    return 0;
}