package contest180126;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;

public class D {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void solve()
	{
		int n = ni();
		char[][] map = nm(n, n);
		
		int ans = 0;
		
		ans = Math.max(ans, go(map));
		ans = Math.max(ans, go(map = rot(map)));
		ans = Math.max(ans, go(map = rot(map)));
		ans = Math.max(ans, go(map = rot(map)));
		ans = Math.max(ans, go(map = rev(map)));
		ans = Math.max(ans, go(map = rot(map)));
		ans = Math.max(ans, go(map = rot(map)));
		ans = Math.max(ans, go(map = rot(map)));
		out.println(ans);
	}
	
	public static char[][] rot(char[][] a)
	{
		int n = a.length, m = a[0].length;
		char[][] b = new char[m][n];
		for(int i = 0;i < n;i++){
			for(int j = 0;j < m;j++){
				b[j][n-1-i] = a[i][j];
			}
		}
		return b;
	}
	
	public static char[][] rev(char[][] a)
	{
		int n = a.length, m = a[0].length;
		char[][] b = new char[n][m];
		for(int i = 0;i < n;i++){
			for(int j = 0;j < m;j++){
				b[i][m-1-j] = a[i][j];
			}
		}
		return b;
	}

	
	int go(char[][] map)
	{
		int n = map.length;
		int ans = 0;
		// horizontal only
		{
			int ct = 0;
			for(int i = 0;i < n;i++){
				if(canput(map, i, 0, i, n-2) || canput(map, i, 1, i, n-1)){
					ct++;
				}
			}
			ans = Math.max(ans, ct);
		}
		// put (0, 0, n-2, 0)
		if(canput(map, 0, 0, n-2, 0)){
			int ct = 1;
			for(int i = 0;i < n-1;i++){
				if(canput(map, i, 1, i, n-1)){
					ct++;
				}
			}
			if(canput(map, n-1, 0, n-1, n-2) || canput(map, n-1, 1, n-1, n-1)){
				ct++;
			}
			ans = Math.max(ans, ct);
		}
		if(canput(map, 1, 0, n-1, 0)){
			int ct = 1;
			for(int i = 1;i < n;i++){
				if(canput(map, i, 1, i, n-1)){
					ct++;
				}
			}
			if(canput(map, 0, 0, 0, n-2) || canput(map, 0, 1, 0, n-1)){
				ct++;
			}
			ans = Math.max(ans, ct);
		}
		// put (0, 0, n-2, 0), (0, n-1, n-2, n-1)
		if(canput(map, 0, 0, n-2, 0) && canput(map, 0, n-1, n-2, n-1)){
			int ct = 2;
			if(canput(map, n-1, 0, n-1, n-2) || canput(map, n-1, 1, n-1, n-1)){
				ct++;
			}
			ans = Math.max(ans, ct);
		}
		// put (0, 0, n-2, 0), (1, n-1, n-1, n-1)
		if(canput(map, 0, 0, n-2, 0) && canput(map, 1, n-1, n-1, n-1)){
			int ct = 2;
			if(canput(map, n-1, 0, n-1, n-2)){
				ct++;
			}
			if(canput(map, 0, 1, 0, n-1)){
				ct++;
			}
			ans = Math.max(ans, ct);
		}
		return ans;
	}
	
	boolean canput(char[][] map, int r1, int c1, int r2, int c2)
	{
		for(int i = r1;i <= r2;i++){
			for(int j = c1;j <= c2;j++){
				if(map[i][j] == '#')return false;
			}
		}
		return true;
	}
	
	void run() throws Exception
	{
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		long s = System.currentTimeMillis();
		solve();
		out.flush();
		if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
//		Thread t = new Thread(null, null, "~", Runtime.getRuntime().maxMemory()){
//			@Override
//			public void run() {
//				long s = System.currentTimeMillis();
//				solve();
//				out.flush();
//				if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
//			}
//		};
//		t.start();
//		t.join();
	}
	
	public static void main(String[] args) throws Exception { new D().run(); }
	
	private byte[] inbuf = new byte[1024];
	public int lenbuf = 0, ptrbuf = 0;
	
	private int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private double nd() { return Double.parseDouble(ns()); }
	private char nc() { return (char)skip(); }
	
	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private long[] nal(int n)
	{
		long[] a = new long[n];
		for(int i = 0;i < n;i++)a[i] = nl();
		return a;
	}
	
	private char[][] nm(int n, int m) {
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private int[][] nmi(int n, int m) {
		int[][] map = new int[n][];
		for(int i = 0;i < n;i++)map[i] = na(m);
		return map;
	}
	
	private int ni() { return (int)nl(); }
	
	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }
}