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

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> veci;
typedef vector<string> vecs;
template<class T,class U> using Hash=unordered_map<T,U>;

#define REP(i, a, n) for(ll i = a; i < n; i++)
#define RREP(i, a, n) for(ll i = n-1; i >= 0; i--)
#define rep(i, n) REP(i, 0, n)
#define rrep(i, n) RREP(i, 0, n)
#define MD 1000000007

template<class T> T read(){T a;cin >> a;return a;}
template<class T> T read(T& a){cin >> a;}
template<class T> void rarr(T a, int n){for(int i = 0; i < n; i++) {cin >> a[i];}}
template<class T> void write(T a){cout << a << endl;}
template<class T> void writes(vector<T> a, char* c = " "){cout << a[0];for(int i = 1; i < a.size(); i++)cout << c << a[i];cout << endl;;}
void write(double a){cout << fixed << setprecision(12) << a << endl;}
template<class T> void warr(T a, int n, char* c = " "){cout << a[0];for(int i = 1; i < n; i++)cout << c << a[i];cout << endl;}
void split(string s, string delim, veci& result){result.clear();string::size_type pos = 0;while(pos != string::npos){string::size_type p = s.find(delim, pos);if(p == string::npos){result.push_back(atoi(s.substr(pos).data()));break;}else {result.push_back(atoi(s.substr(pos, p - pos).data()));}pos = p + delim.size();}}
void split(string s, string delim, vecs& result){result.clear();string::size_type pos = 0;while(pos != string::npos){string::size_type p = s.find(delim, pos);if(p == string::npos){result.push_back(s.substr(pos));break;}else {result.push_back(s.substr(pos, p - pos));}pos = p + delim.size();}}
ll gcd(ll a, ll b){while(true){ll k = a % b;if(k == 0)return b;a = b;b = k;}}
ll comb(ll n, ll m){ll p=1;m=min(m,n-m);for(ll i=1;i<=m;i++){p*=n-i+1;p/=i;}return p;}

int main(void)
{
    int n=read<int>();
    int a[6][6]={0};
    int k=0;
    rep(i,n){
        string str=read<string>();
        rep(j,str.size()){
            if(str[j]=='x')a[i][j]=-1;
            else if(str[j]=='o')a[i][j]=1;
            else if(str[j]=='-')k++;
        }
    }
    if(n==1){write(1);return 0;}
    k=(int)pow(2,k/2);
    int res=n;
    rep(i,k){
        pair<int,int> b[6];
        int p=0;
        rep(z,n){b[z].second=z;b[z].first=0;}
        REP(j,1,n){
            REP(l,0,j){
                if(a[j][l]==1)
                    b[j].first++;
                else if(a[j][l]==-1)
                    b[l].first++;
                else if(a[j][l]==0){
                    if((i&(1<<p))>0)b[j].first++;
                    else b[l].first++;
                    p++;
                }
            }
        }
        sort(b,b+n,greater<pair<int,int>>());
        if(b[0].second==0)
            res=1;
        int xx=1;
        REP(x,1,n){
            if(b[x].first!=b[x-1].first){xx++;}
            if(b[x].second==0)break;
        }
        res=min(res,xx);
    }
    write(res);
	return 0;
}