import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.TreeSet;
public class Main {
	public static int w;
	public static int k;
	public static int n;
//	public static int[][] dp;
	public static int[] a;
	public static int[] b;
	public static List<double[]> list = new ArrayList<double[]>();
	public static TreeSet<Integer> set = new TreeSet<Integer>();
//	public static PriorityQueue<Integer> pq = new PriorityQueue<Integer>();
	public static void main(String[] args) throws NumberFormatException, IOException{

		ContestScanner in = new ContestScanner();
		n = in.nextInt();
		int[][] s = new int[n][n];
		String line;
		int rest = 0;
		for(int i=0; i<n; i++){
			line = in.nextToken();
			for(int j=0; j<n; j++){
				char c = line.charAt(j);
				if(c == '#') s[i][j] = 8;
				else if(c == '-'){
					s[i][j] = 0;
					rest++;
				}
				else if(c == 'o') s[i][j] = 1;
				else s[i][j] = 2;
			}
		}
		rest /= 2;
//		for(int i=0; i<n; i++){
//			if(s[0][i] == 0){
//				s[0][i] = 1;
//				s[i][0] = 2;
//				rest--;
//			}
//		}
		
		System.out.println(dfs(rest, s));
		
	}
	
	public static int dfs(int rest, int[][] buttle){
//		System.err.println("rest:"+rest);
		if(rest == 0){
			int count = 0;
//			int[] rank = new int[n];
			for(int i=n-1; i>=0; i--){
				count = 0;
				for(int j=0; j<n; j++){
					count += buttle[i][j] == 1 ? 1 : 0;
//					System.err.print(buttle[i][j]);
				}
//				System.err.println();
				set.add(count);
				
			}
			int i = 0;
			while(set.pollLast() != count) i++;
			set = new TreeSet<Integer>();
//			System.err.println(i);
//			System.err.println();
			return i+1;
		}else{
			int[][] copy = new int[n][n];
			boolean changed = false;
			for(int i=0; i<n; i++){
				for(int j=0; j<n; j++){
					copy[i][j] = buttle[i][j];
				}
			}
			for(int i=0; i<n; i++){
				for(int j=0; j<n; j++){
					if(!changed && buttle[i][j] == 0){
						changed = true;
						copy[i][j] = 1;
						copy[j][i] = 2;
						buttle[i][j] = 2;
						buttle[j][i] = 1;
					}
				}
			}
			
			return Math.min(dfs(rest-1, copy), dfs(rest-1, buttle));
			
		}
	}
	
}



class Node{
	int id;
	List<Node> edge = new ArrayList<Node>();
	public Node(int id){
		this.id = id;
	}
	public void createEdge(Node node){
		edge.add(node);
	}
}

class MyMath{
	public static long fact(long n){
		long res = 1;
		while(n > 0){
			res *= n--;
		}
		return res;
	}
	public static long[][] pascalT(int n){
		long[][] tri = new long[n][];
		for(int i=0; i<n; i++){
			tri[i] = new long[i+1];
			for(int j=0; j<i+1; j++){
				if(j == 0 || j == i){
					tri[i][j] = 1;
				}else{
					tri[i][j] = tri[i-1][j-1] + tri[i-1][j];
				}
			}
		}
		return tri;
	}
}

class MyComp implements Comparator<Integer>{
	public int compare(Integer arg0, Integer arg1) {
		return arg0 - arg1;
	}
}
//
//class MyCompB implements Comparator<int[]>{
//	public int compare(int[] arg0, int[] arg1) {
//		return arg0[1] - arg1[1];
//	}
//}

class ContestScanner{
	private BufferedReader reader;
	private String[] line;
	private int idx;
	public ContestScanner() throws FileNotFoundException{
		reader = new BufferedReader(new InputStreamReader(System.in));
	}
	
	public String nextToken() throws IOException{
		if(line == null || line.length <= idx){
			line = reader.readLine().trim().split(" ");
			idx = 0;
		}
		return line[idx++];
	}
	
	public long nextLong() throws IOException, NumberFormatException{
		return Long.parseLong(nextToken());
	}
	
	public int nextInt() throws NumberFormatException, IOException{
		return (int)nextLong();
	}
	
	public double nextDouble() throws NumberFormatException, IOException{
		return Double.parseDouble(nextToken());
	}
}