#include<cstdio>
#include<vector>


using namespace std;
using vi=vector<int>;
using vvi=vector<vector<int> >;

struct count_t
{
	int win, lose;
};


int count(vvi& s)
{
	int n=s.size();
	vi c(n);
	int rank=0;
	int b[n]={0};

	for(int y=0;y<n;y++)
	{
		for(int x=0;x<n;x++)
		{
			if(s[y][x]=='o') c[y]++;
		}
		b[c[y]]++;
	}

	for(int i=n-1;i>=0;i--)
	{
		if(b[i]) rank++;
		if(c[0]==i) return rank;
	}
	return 999;
}


int min_u(int& m, int v)
{
	if(m>v)
	{
		m=v;
		return 1;
	}
	return 0;
}


void vvi_dump(const vvi& s)
{
	unsigned x, y;
	for(y=0;y<s.size();y++)
	{
		for(x=0;x<s[y].size();x++) printf("%c ", s[y][x]);
		printf("\n");
	}
	printf("\n");
}


int solve(vvi& w)
{
	int n=w.size();
	int ret=n;

	for(int y=1;y<n;y++)
	{
		for(int x=y+1;x<n;x++)
		{
			if(w[y][x]!='-') continue;

			w[y][x]='o', w[x][y]='x';
			min_u(ret, solve(w));
			w[y][x]='x', w[x][y]='o';
			min_u(ret, solve(w));
			w[y][x]='-', w[x][y]='-';
			return ret;
		}
	}

//	vvi_dump(w);

	return count(w);
}


int main(void)
{
	vvi s;
	vector<count_t> c;
	int n;
	int x, y;

	while(scanf("%d", &n)==1)
	{
		c.resize(n);
		s.resize(n);
		for(y=0;y<n;y++)
		{
			char buf[6+2];

			s[y].resize(n);
			scanf("%s", buf);
			for(x=0;x<n;x++)
			{
				s[y][x]=buf[x];
			}
		}

		for(x=0;x<n;x++)
		{
			if(s[0][x]=='-')
			{
				s[0][x]='o';
				s[x][0]='x';
			}
		}

		printf("%d\n", solve(s));
	}

	return 0;
}