import java.util.*;
 

public class Main {
	static int ansa =7;
	static char[][] kekka;
	static char[][] copy(char[][] from){
		int aa = from[0].length;
		char[][] to = new char[aa][aa];
		for(int i=0;i<aa;i++){
			for(int j=0;j<aa;j++){
				to[i][j]=from[i][j];
			}
		}
		return to;
	}
	static void dfs(char[][] map,int n){
		char[][] map1 = copy(map);
		for(int i=0;i<n;i++){
			for(int j=0;j<n;j++){
				if(map[i][j]=='-'){
					map1[i][j]='o';
					map1[j][i]='x';
					dfs(map1,n);
					map1[i][j]='x';
					map1[j][i]='o';
					dfs(map1,n);
					return;
				}
			}
		}
		int[] kazu = new int[n];
		for(int i=0;i<n;i++){
			for(int j=0;j<n;j++){
				if(map[i][j]=='o') kazu[i]++;
			}
		}
		int aa=kazu[0];
		Arrays.sort(kazu);
		int ans=1;
		int now=kazu[n-1];
		for(int i=n-1;i>=0;i--){
			if(kazu[i]<now){
				ans++;
				now=kazu[i];
			}
			if(now==aa){
				break;
			}
		}
		ansa=Math.min(ansa,ans);
		
	}
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n= sc.nextInt();
		kekka= new char[n][n];
		int[] kazu = new int[n];
		for(int i=0;i<n;i++){
			String ss=sc.next();
			for(int j=0;j<n;j++){
				kekka[i][j]=ss.charAt(j);
			}
		}
		dfs(kekka,n);
		System.out.println(ansa);
	}
}