import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws FileNotFoundException {
		long t = System.currentTimeMillis();
		new Main().run();
		System.err.println(System.currentTimeMillis() - t);
	}
	
	void run() {
		Scanner sc = new Scanner(System.in);
		int N=sc.nextInt();
		char[][] m=new char[N][N];
		for(int i=0;i<N;++i)m[i]=sc.next().toCharArray();
		int ans=Integer.MAX_VALUE/3;
		for(int s=0;s<1L<<(N*(N-1)/2);++s) {
			int[] a=new int[N];
			int pos=0;
			for(int i=0;i<N;++i) {
				for(int j=i+1;j<N;++j) {
					if(m[i][j]=='-') {
						if((s>>pos)%2==1) {
							a[i]++;
						}else {
							a[j]++;
						}
					}else if(m[i][j]=='o'){
						++a[i];
					}else {
						++a[j];
					}
					++pos;
				}
			}
			int get=a[0];
			Arrays.sort(a);
			int cur=a.length-1;
			int tmp=1;
			while(a[cur]!=get) {
				--cur;
				if(a[cur]!=a[cur+1])++tmp;
			}
			ans=Math.min(ans, tmp);
		}
		System.out.println(ans);
	}


	static void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}

}