#include <iostream>

using namespace std;

const int MAXN = 6;

int N;
string S[MAXN];
int win[MAXN];

int rank0() {
	for (int i = 0; i < N; i++) {
		win[i] = 0;
	}
	int win0 = 0;
	for (int i = 0; i < N; i++) {
		if (S[0][i] == 'o') {
			win0++;
		}
	}
	for (int i = 1; i < N; i++) {
		int w = 0;
		for (int j = 0; j < N; j++) {
			if (S[i][j] == 'o') {
				w++;
			}
		}
		win[w]++;
	}
	int rank = 1;
	for (int i = N - 1; i > win0; i--) {
		if (win[i] > 0) {
			rank++;
		}
	}
	return rank;
}

int best(int idx0, int idx1) {
	if (idx0 == N - 1) {
		return rank0();
	} else if (idx1 == N) {
		return best(idx0 + 1, idx0 + 2);
	} else if (S[idx0][idx1] != '-') {
		return best(idx0, idx1 + 1);
	} else {
		int best_rank = N;
		S[idx0][idx1] = 'o';
		S[idx1][idx0] = 'x';
		best_rank = min(best_rank, best(idx0, idx1 + 1));
		S[idx0][idx1] = 'x';
		S[idx1][idx0] = 'o';
		best_rank = min(best_rank, best(idx0, idx1 + 1));
		S[idx0][idx1] = S[idx1][idx0] = '-';
		return best_rank;
	}
}

int main() {
	cin >> N;
	for (int i = 0; i < N; i++) {
		cin >> S[i];
	}
	cout << best(0, 1);
	return 0;
}