#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <iomanip>
using namespace std;
#define INF 1e9
#define PI acos(-1)
typedef long long ll;

int n;
char game[6][6];

int dfs(int x) {
	if (x == 0) {
		int win[6] = {0};
		for (int i = 0; i < n; i++)for (int j = 0; j < n; j++) {
			win[i] += game[i][j] == 'o';
		}
		int ret = 0;
		for (int i = n;; i--) {
			for (int j = 0; j < n; j++)
				if (win[j] == i) { ret++; break; }
			if (win[0] == i) return ret;
		}
	}
	else {
		int ret = INT_MAX;
		for (int i = 0; i < n; i++)for (int j = 0; j < i; j++) {
			if (game[i][j] == '-') {
				game[i][j] = 'o'; game[j][i] = 'x';
				ret = min(ret, dfs(x - 1));
				game[i][j] = 'x'; game[j][i] = 'o';
				ret = min(ret, dfs(x - 1));
				game[i][j] = game[j][i] = '-';
				return ret;
			}
		}
		return ret;
	}
}

int main() {
	cin >> n;
	for (int i = 0; i < n; i++)cin >> game[i];
	int bar = 0;
	for (int i = 0; i < n; i++)for (int j = 0; j < i; j++)bar += game[i][j] == '-';
	cout << dfs(bar) << endl;
	return 0;
}