#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 5;
int n, nxt[maxn];
char s[maxn];

void cal_nxt() { 
	nxt[1] = 0;
	for (int i = 2, j = 0; i <= n; i++) {
		while (j && s[j+1] != s[i])
			j = nxt[j];
		if (s[j+1] == s[i]) j++;
		nxt[i] = j;
	}
}
int main() {
	scanf("%d", &n);
	scanf("%s", s+n+1);	// s[n+1..n+n]
	strncpy(s+1, s+n+1, n); // s[1..n]
	reverse(s+1, s+n+1);
	n *= 2;
	cal_nxt();
	int p = n;
	while (p > n/2)
		p = nxt[p];
	printf("%d\n", n/2 - p);
	return 0;
}