#include <bits/stdc++.h>
using namespace std;

using pii = pair<int, int>;

int N;
char B[10][10];
int h = 0;
int ans = 100;

void print() {
   for (int i = 0; i < N; i++) {
      for (int j = 0; j < N; j++) {
         printf("%c", B[i][j]);
      }
      puts("");
   }
}

bool exist() {
   for (int i = 0; i < N; i++) {
      for (int j = 0; j < N; j++) {
         if (B[i][j] == '-') return true;
      }
   }
   return false;
}

int result() {
   map<int, int> mp;
   for (int i = 0; i < N; i++) {
      mp[i] = 0;
   }
   for (int i = 0; i < N; i++) {
      for (int j = 0; j < N; j++) {
         if (B[i][j] == 'o') {
            mp[i]++;
         }
      }
   }
   set<int> S;
   for (auto x:mp) {
      S.insert(x.second);
   }
   int cnt = 1;
   for (auto itr = S.rbegin(); itr != S.rend(); itr++) {
      if (*itr == mp[0]) {
         return cnt;
      }
      cnt++;
   }
   return 100;
}

void dfs() {
   if (!exist()) {
      // print();
      // int res = result();
      // printf("res: %d\n", res);
      // puts("---------------");
      ans = min(ans, result()); 
   }

   for (int i = 0; i < N; i++) {
      for (int j = 0; j < N; j++) {
         if (B[i][j] == '-') {
            B[i][j] = 'o';
            B[j][i] = 'x';
            dfs();
            B[i][j] = 'x';
            B[j][i] = 'o';
            dfs();
            B[i][j] = '-';
            return;
         }
      }
   }
}

int main() {
   cin >> N;
   for (int i = 0; i < N; i++) { cin >> B[i]; }

   for (int i = 0; i < N; i++) {
      if (B[0][i] == '-') {
         B[0][i] = 'o';
         B[i][0] = 'x';
      }
   }

   for (int i = 0; i < N; i++) {
      if (B[0][i] == '-') {
         B[0][i] = 'o';
         B[i][0] = 'x';
      }
   }

   dfs();
   cout << ans << endl;

   return 0;
}