#include <iostream>

using namespace std;

string A[100][100];
int main(int argc, const char *argv[])
{
	int N;
	cin >> N;
	for (int i = 0; i < N; i++) {
		for (int j = 0; j < N; j++) {
			cin >> A[i][j];
		}
	}
	int ret = -2;
	for (int j = 0; j < N; j++) {
		int cnt = 0;
		for (int i = 0; i < N; i++) {
			if (A[i][j] == "nyanpass") cnt++;
		}
		if (cnt == N - 1) {
			if (ret == -2) {
				ret = j;
			}
			else {
				ret = -2;
				break;
			}
		}
	}
	cout << ret + 1 << endl;
	return 0;
}