#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  int n;
  cin >> n;
  vector<string> bd(n);
  REP (i, n) cin >> bd[i];

  int rm = 0;
  REP (i, n) REP (j, i) if (bd[i][j] == '-') ++rm;

  int ret = 1e8;
  REP (mask, 1<<rm) {
    int k = 0;
    vector<string> tmp = bd;
    REP (i, n) REP (j, i) {
      if (tmp[i][j] == '-') {
        if (mask & 1<<k) {
          tmp[i][j] = 'o';
          tmp[j][i] = 'x';
        } else {
          tmp[i][j] = 'x';
          tmp[j][i] = 'o';
        }
        ++k;
      }
    }
    vector<int> wins(n);
    REP (i, n) REP (j, n) {
      if (tmp[i][j] == 'o')
        ++wins[i];
    }
    int rank = 0;
    for (int i = n; i >= 0; i--) {
      if (find(wins.begin(), wins.end(), i) != wins.end()) {
        ++rank;
        if (wins[0] == i)
          break;
      }
    }
    
    ret = min(ret, rank);
  }

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