#include <bits/stdc++.h>

#define show(x) cout << #x << " = " << x << endl

using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v)
{
    os << "sz=" << v.size() << "\n[";
    for (const auto& p : v) {
        os << p << ",";
    }
    os << "]\n";
    return os;
}

template <typename S, typename T>
ostream& operator<<(ostream& os, const pair<S, T>& p)
{
    os << "(" << p.first << "," << p.second
       << ")";
    return os;
}


constexpr ll MOD = 1e9 + 7;

template <typename T>
constexpr T INF = numeric_limits<T>::max() / 100;

int main()
{
    int N;
    cin >> N;
    vector<vector<int>> s(N, vector<int>(N, 0));
    vector<pii> yet;
    for (ll i = 0; i < N; i++) {
        for (ll j = 0; j < N; j++) {
            char c;
            cin >> c;
            if (c == 'o') {
                s[i][j] = 1;
                s[j][i] = -1;
            } else if (c == 'x') {
                s[i][j] = -1;
                s[j][i] = 1;
            } else if (c == '-') {
                s[i][j] = 0;
                if (i < j) {
                    yet.push_back(make_pair(i, j));
                }
            }
        }
    }

    const int maximum = 1 << (yet.size());
    int mini = 1000000;
    for (int i = 0; i < maximum; i++) {
        int num = i;
        for (int j = 0; j < yet.size(); j++) {
            const bool b = num % 2;
            const int I = yet[j].first;
            const int J = yet[j].second;
            if (b) {
                s[I][J] = 1;
                s[J][I] = -1;
            } else {
                s[J][I] = 1;
                s[I][J] = -1;
            }
            num /= 2;
        }
        vector<int> scores(N + 1, 0);
        int s0 = 0;
        for (int a = 0; a < N; a++) {
            int n = 0;
            for (int b = 0; b < N; b++) {
                if (s[a][b] == 1) {
                    n++;
                }
            }
            if (a == 0) {
                s0 = n;
            }
            scores[n]++;
        }

        int ans = 0;
        for (int g = N; g >= s0; g--) {
            if (scores[g] > 0) {
                ans++;
            }
        }
        mini = min(ans, mini);
    }

    cout << mini << endl;

    return 0;
}