#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <cmath>
#include <iostream>
#include <queue>
#include <list>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;

struct ST {
  int s;
  int i;
};
bool operator<(const ST& a, const ST& b){
  if(a.s == b.s) return a.i < b.i;
  return a.s > b.s;
}

int ret;

void dfs(vector<string>& v){
  rep(i,v.size()){
    rep(j,v.size()){
      if(v[i][j] == '-'){
        v[i][j] = 'o';
        v[j][i] = 'x';
        dfs(v);
        v[i][j] = 'x';
        v[j][i] = 'o';
        dfs(v);
        v[i][j] = '-';
        v[j][i] = '-';
        return;
      }
    }
  }

  vector<int> w(v.size(), 0);
  rep(i,v.size()){
    rep(j,v.size()){
      if(v[i][j]=='o') w[i]++;
    }
  }
  vector<ST> ww;
  rep(i,v.size()) ww.push_back((ST){w[i],i});
  sort(ALLOF(ww));
  
  rep(i,v.size()){
    if(ww[i].i == 0){
      ret = min(ret, i+1);
      return;
    }
  }
}


int main(){
  int N;
  vector<string> v;
  cin >> N;
  rep(i,N){
    string str;
    cin >> str;
    v.push_back(str);
  }

  ret = 10;

  dfs(v);

  cout << ret << endl;
  
  return 0;
}