#include<iostream>
#include<iomanip>
#include<string>
#include<algorithm>
#include<vector>
#include<set>
#include<list>
#include<queue>
#include<math.h>
#include<bitset>
using ll = long long;
using namespace std;

int main(){
    int n, mrank = 10;
    cin >> n;
    vector<string> l(n);
    for (int i = 0; i < n; i++) cin >> l[i];
    deque<vector<string>> dq;
    dq.push_back(l);
    while (!dq.empty()) {
        vector<string> tmp = dq.front();
        vector<int> pt;
        dq.pop_front();
        int mypt;
        bool nfill = false;
        for (int i = 0; i < n; i++){
            for (int j = 0; j < n; j++){
                if (tmp[i][j] == '-'){
                    tmp[i][j] = 'o';
                    tmp[j][i] = 'x';
                    dq.push_back(tmp);
                    tmp[i][j] = 'x';
                    tmp[j][i] = 'o';
                    dq.push_back(tmp);
                    nfill = true;
                    break;
                }
            }
            if (nfill) break;
        }
        if (nfill) continue;
        for (int i = 0; i < n; i++){
            int cnt = 0;
            for (int j = 0; j < n; j++){
                if (tmp[i][j] == 'o') cnt++;
            }
            pt.push_back(cnt);
        }
        mypt = pt[0];
        sort(pt.begin(), pt.end(), greater());
        int rank = 1, maxpt = pt[0];
        for (int i = 0; i < n; i++){
            if (maxpt > pt[i]){
                rank++;
                maxpt = pt[i];
            }
            if (mypt == pt[i]){
                if (mrank > rank) mrank = rank;
            }
        }
    }
    cout << mrank << endl;
}