#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int,int> pii; typedef vector<pair<int,int> > vpii; typedef long long ll;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

int main() {
	int N;
	while(cin >> N) {
		char s[6][7];
		rep(i, N)
			cin >> s[i];
		int m = N * (N-1) / 2;
		int ans = INF;
		rep(i, 1 << m) {
			bool ok = true;
			int t = 0;
			int u[6] = {};
			rep(j, N) rep(k, j) {
				if(s[j][k] != '-')
					ok &= (s[j][k] == 'o') == ((i >> t & 1) != 0);
				if(i >> t & 1)
					++ u[j];
				else
					++ u[k];
				++ t;
			}
			if(!ok) continue;
			int x = 0;
			reu(j, u[0] + 1, N) {
				bool y = false;
				rep(k, N)
					y |= u[k] == j;
				x += y;
			}
			amin(ans, x + 1);
		}
		printf("%d\n", ans);
	}
	return 0;
}