#include<iostream>
#include<sstream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
#include<vector>
#include<cmath>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<numeric>
#include<functional>
#include<complex>

using namespace std;
#define BET(a,b,c) ((a)<=(b)&&(b)<(c))
#define FOR(i,n) for(int i=0,i##_end=(int(n));i<i##_end;i++)
#define SZ(x) (int)(x.size())
#define ALL(x) (x).begin(),(x).end()
#define MP make_pair
#define FOR_EACH(it,v) for(__typeof(v.begin()) it=v.begin(),it_end=v.end() ; it != it_end ; it++)
typedef vector<int> VI;
typedef vector<VI> VVI;

int main()
{
    int n;
    cin>>n;
    vector<string> dat(n);
    FOR(i,n) cin>>dat[i];
    VI point(n);
    vector<pair<int,int> > unknown;
    FOR(i,n) FOR(j,n) if(i != j){
        if(dat[i][j] == 'o'){
            point[i]++;
        }else if(dat[i][j] == '-' && i < j){
            unknown.push_back(MP(i,j));
        }
    }
    int ans = 11111;
    FOR(i,1<<SZ(unknown)){
        VI result(point);
        FOR(j,SZ(unknown)) if(i & (1<<j)) {
            result[unknown[j].first]++;
        } else {
            result[unknown[j].second]++;
        }
        VI a;
        FOR(j,n) {
            if(result[0] < result[j]) a.push_back(result[j]);
        }
        sort(ALL(a));
        a.erase(unique(a.begin(),a.end()),a.end());
        //FOR(j,n) cout<<" "<<result[j]; cout<<" -> " << SZ(a)<<endl;
        ans = min(ans, SZ(a) + 1);
    }
    cout<<ans<<endl;
    return 0;
}