#include <iostream>

using namespace std;

int N;
string s;
int main(void) {
	while (cin >> N && N) {
		cin >> s;
		int i;
		for (i = 0; i < N - 1; i++) {
			if (s[i] == 'x' && s[i+1] == 'x') break;
		}
		cout << i + 1 << endl;
	}
}