#include <iostream>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>	// require sort next_permutation count __gcd reverse etc.
#include <cstdlib>	// require abs exit atof atoi 
#include <cstdio>		// require scanf printf
#include <functional>
#include <numeric>	// require accumulate
#include <cmath>		// require fabs
#include <climits>
#include <limits>
#include <cfloat>
#include <iomanip>	// require setw
#include <sstream>	// require stringstream 
#include <cstring>	// require memset
#include <cctype>		// require tolower, toupper
#include <fstream>	// require freopen
#include <ctime>		// require srand
#define rep(i,n) for(int i=0;i<(n);i++)
#define ALL(A) A.begin(), A.end()
#define INF 10

/*
	No.43 野球の試合	
*/

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

char t[10][10];
char u[10][10];

bool cmp (P a, P b ){
	if (a.first != b.first ){
		return a.first > b.first;
	} // end if
	
	return a.second < b.second;
}

int solve (int N ){
	vector<P> score(N );
	rep (i, N ) {
		int win = 0;
		rep (j, N )
			if (u[i][j] == 'o' ) win++;
		score[i] = P (win, i );
	} // end rep

	sort (ALL (score ), cmp );
	vector<int> rank (N, 0 );
	for (int i = 1; i < N; i++ )
		rank[i] = (score[i-1].first == score[i].first ? rank[i-1] : rank[i-1]+1 );  
		
	rep (i, N )
		if (score[i].second == 0 ){
			return (rank[i] + 1 );
		} // end if

	return -1;
}

int main()
{
	map<int,P > comb; comb.clear();
	int k = 0;
	for (int i = 1; i < 6; i++ ) rep (j, i ) comb[k++] = P (i, j ); 

	memset (t, 0, sizeof (t ) );
	ios_base::sync_with_stdio(0);
	int N; cin >> N;
	rep (i, N ) rep (j, N ) cin >> t[i][j];

	//総当たりで順位を決める
	int res = INF;
	for (int cnt = 0; cnt < (1<<15 ); cnt++ ){
		memset (u, 0, sizeof (u ) );
		rep (i, N ) rep (j, N ) u[i][j] = t[i][j];
		rep (j, 15 ){
			int row = comb[j].first;
			int col = comb[j].second;
			if (u[row][col] == '-' ){
				if (cnt & (1<<j ) ){
					u[row][col] = 'o';
					u[col][row] = 'x';
				}else{
					u[row][col] = 'x';
					u[col][row] = 'o';
				} // end if
			} // end if
		} // end rep
		int curr = solve (N );
//		cerr << "curr: " << curr << endl;
		res = min (res, curr );
	} // end for

	cout << res << endl;

	return 0;
}