#define _CRT_SECURE_NO_WARNINGS
#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#include <stack>
#include <array>
#include <fstream>

#define REP(i,n) for(int (i) = 0;(i) < (n) ; ++(i))
#define REPA(a,i,n) for(int (i) = (a) ; (i) < (n) ; ++(i))
#if defined(_MSC_VER)||__cplusplus > 199711L
#define AUTO(r,v) auto r = (v)
#else
#define AUTO(r,v) typeof(v) r = (v)
#endif
#define ALL(c) (c).begin() , (c).end()
#define EACH(it,c) for(AUTO(it,(c).begin());it != (c).end();++it)
#define LL long  
#define int LL
#define INF  99999999
#define DEV 1000000007
#define QUICK_CIN ios::sync_with_stdio(false); cin.tie(0);
using namespace std;

string t[7];
int n;

struct P{
	int x, y;
};

vector<P> aa;

int check()
{
	int win[7] = { 0 };

	REP(i, n){
		REP(j,n)
		if (t[i][j] == 'o'){
			win[i]++;
		}
	}
	int a = win[0];
	sort(win, win + n,greater<int>());
	int aaa = win[0];
	int it = 1;
	REP(i, n){
		if (aaa != win[i]){
			aaa = win[i];
			it++;
		}
		if (a == win[i]){
			break;
		}
	}
	return it;
}

int solve()
{
	if (!aa.size()){
		return check();
	}

	int kk;
	auto x = aa.back();
	aa.pop_back();
	t[x.x][x.y] = 'o';
	t[x.y][x.x] = 'x';
	kk = solve();
	t[x.x][x.y] = 'x';
	t[x.y][x.x] = 'o';
	kk = min(kk,solve());
	aa.push_back(x);

	return kk;
}

signed main()
{
	QUICK_CIN;
	//ifstream cin("debug.txt");
	//ofstream cout("result.txt");



	cin >> n;

	REP(i, n){
		cin >> t[i];
	}

	REP(i, n){
		t[i][i] = '#';
	}

	REP(i, n){
		REPA(i, j, n){
			if (t[i][j] == '-'){
				aa.push_back({ i, j });
			}
		}
	}

	cout << solve() << endl;

	return 0;

}