#include <iostream>
#include <cstring>
#include <utility>
#include <vector>
#include <algorithm>
using namespace std;

typedef pair<int, int> P;   // (勝利数, チーム)

const int kMAX_N = 6;

int N, answer;
char S[kMAX_N][kMAX_N];
int result[kMAX_N][kMAX_N];

void Judge() {
    vector<P> table;
    for (int i = 0; i < N; i++) {
        int win = 0;
        for (int j = 0; j < N; j++) {
            if (result[i][j]) win++;
        }
        table.push_back(make_pair(win, i));
    }
    sort(table.begin(), table.end(), greater<P>());

    int rank = 1, i = 0;
    while (i < N) {
        if (i > 0 && table[i - 1].first != table[i].first) rank++;
        if (table[i].second == 0) break;
        i++;
    }
    answer = min(answer, rank);
}

// 有りうる勝敗のパターンを全列挙する
void rec(int me, int enemy) {
    if (me == N) {   // 結果判定
        Judge();
        return;
    }
    if (S[me][enemy] == '-') {
        for (int i = 0; i < 2; i++) {
            result[me][enemy] = i;
            result[enemy][me] = (i + 1) % 2;
            if (enemy == N - 1) rec(me + 1, 0);
            else rec(me, enemy + 1);
        }
    } else {
        if (S[me][enemy] == 'o') {
            result[me][enemy] = 1;
            result[enemy][me] = 0;
        } else if (S[me][enemy] == 'x') {
            result[me][enemy] = 0;
            result[enemy][me] = 1;
        }
        if (enemy == N - 1) rec(me + 1, 0);
        else rec(me, enemy + 1);
    }
}

void Solve() {
    answer = kMAX_N;
    memset(result, -1, sizeof(result));
    rec(0, 0);
    cout << answer << endl;
}

int main() {
    cin >> N;

    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            cin >> S[i][j];
        }
    }

    Solve();

    return 0;
}