#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <complex>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <iomanip>
#include <assert.h>
#include <array>
#include <cstdio>
#include <cstring>
#include <random>
#include <functional>
#include <numeric>
#include <bitset>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)
#define all(c) (c).begin(), (c).end()
#define zero(a) memset(a, 0, sizeof a)
#define minus(a) memset(a, -1, sizeof a)
template<class T1, class T2> inline bool minimize(T1 &a, T2 b) { return b < a && (a = b, 1); }
template<class T1, class T2> inline bool maximize(T1 &a, T2 b) { return a < b && (a = b, 1); }

typedef long long ll;
int const inf = 1<<29;

int main() {

  int N; cin >> N;
  vector<string> F(N); rep(i, N) cin >> F[i];
  vector<pair<int, int>> remains;
  rep(i, N) REP(j, i+1, N) if(F[i][j] == '-') remains.emplace_back(i, j);
  int ans = N;
  rep(S, 1<<remains.size()) {
    rep(i, remains.size()) F[remains[i].first][remains[i].second] = "xo"[S>>i&1], F[remains[i].second][remains[i].first] = "ox"[S>>i&1];
    vector<int> cnts(N); rep(i, N) cnts[i] = count_if(all(F[i]), [](char c){ return c == 'o'; });
    vector<int> win(N); iota(all(win), 0);
    sort(all(win), [&](int a, int b){
      return cnts[a] != cnts[b] ? cnts[a] > cnts[b] : F[a][b] == 'o';
    });

    int s = cnts[win[0]];
    int rank = 1;
    rep(i, N) {
      if(s > cnts[win[i]]) { rank ++; s = cnts[win[i]]; }
      if(s == cnts[0]) { break; }
    }
    minimize(ans, rank);
  }
  cout << ans << endl;

  return 0;
}