#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n);i++)
#define sz(x) int(x.size())
typedef long long ll;
typedef long double ld;
typedef pair<int,int> P;

int main() {
  int n;
  cin >> n;
  vector<string> s(n);
  rep(i,n) cin >> s[i];
  vector<int> a;
  vector<int> cost(n, 0);

  for (int i = 0; i < n; i++) {
    for (int j = i + 1; j < n; j++) {
      if (s[i][j] == '-') a.emplace_back(i * n + j);
      if (s[i][j] == 'o') cost[i]--;
      if (s[i][j] == 'x') cost[j]--;
    }
  }

  int m = a.size();
  int res = 1000;
  for (int bit = 0; bit < (1 << m); bit++) {
    auto tmp = cost;
    for (int i = 0; i < m; i++) {
      int u = a[i] / n, v = a[i] % n;
      if (bit & (1 << i)) tmp[u]--;
      else tmp[v]--;
    }

    int cur = tmp[0];
    sort(tmp.begin(), tmp.end());
    tmp.erase(unique(tmp.begin(), tmp.end()), tmp.end());
    int x = lower_bound(tmp.begin(), tmp.end(), cur) - tmp.begin();
    x++;
    res = min(res, x); 
  }

  cout << res << endl;

  return 0;
}