#include <iostream>
#include <set>
#include <vector>
#include <string>
#include <algorithm>
using namespace std;
typedef long long ll;
#define REP(i, n)           for(int(i)=0;(i)<(n);++(i))

int N;
int maxrank = 6;
string sv[6];

void check(){
    set<int> s;
    int w = 0;
    REP(i,N){
        //cerr << sv[i] << endl;
        int win = 0;
        REP(j,N) if(sv[i][j] == 'o') win++;
        if(i == 0) w = win;
        s.insert(win);
    }
    int rank = 1;
    for(auto it = s.rbegin(); it != s.rend(); ++it){
        if(*it > w) rank++; else break;
    }
    maxrank = min(maxrank, rank);
}

void dfs(int i, int j){
    if(j == N) return dfs(i+1,0);
    if(i == N) return check();

    if(sv[i][j] != '-') return dfs(i,j+1);
    sv[i][j] = 'o'; sv[j][i] = 'x';
    dfs(i,j+1);
    sv[i][j] = 'x'; sv[j][i] = 'o';
    dfs(i,j+1);
    sv[i][j] = sv[j][i] = '-';
}

int main(){
    cin >> N;
    REP(i,N) cin >> sv[i];
    dfs(0,0);
    cout << maxrank << endl;
    return 0;
}