#include "bits/stdc++.h"
using namespace std;

#define DEBUG(x) cout<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cout<<#v<<":";for(int i=0;i<v.size();i++) cout<<" "<<v[i]; cout<<endl

typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
const int inf = 1000000001;
const ll INF = 2e18 * 2;
#define MOD 1000000007
#define mod 1000000009
#define pi 3.14159265358979323846
#define Sp(p) cout<<setprecision(15)<< fixed<<p<<endl;
int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 };
int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };


int main() {
	int i, j, k, n;
	cin >> n;
	vector<vector<vector<char> > > s(4, vector<vector<char> >(n, vector<char>(n)));
	for (i = 0; i < n; i++) {
		for (j = 0; j < n; j++) {
			cin >> s[0][i][j];
			s[1][i][j] = s[2][i][j] = s[3][i][j] = s[0][i][j];
		}
	}
	for (i = 0; i < n; i++) {
		reverse(s[1][i].begin(), s[1][i].end());
		reverse(s[3][i].begin(), s[3][i].end());
	}
	for (i = 0; i < n; i++) {
		for (j = 0; j < n / 2; j++) {
			swap(s[2][i][j], s[2][i][n - 1 - j]);
			swap(s[3][i][j], s[3][i][n - 1 - j]);
		}
	}

	int ans = 0;
	bool flag = true;
	for (i = 0; i < n; i++) {
		if (s[0][0][i] == '#' || s[0][n - 1][i] == '#' || s[0][i][0] == '#' || s[0][i][n - 1] == '#') {
			flag = false;
			break;
		}
	}
	if (flag) {
		ans = 4;
	}
	for (i = 0; i < 4; i++) {
		int cnt = 0;
		for (j = 0; j < n; j++) {
			bool flag = true;
			for (k = 1; k < n - 1; k++) {
				if (s[i][j][k] == '#') {
					flag = false;
					break;
				}
			}
			if (flag && (s[i][j][0] == '.' || s[i][j][n - 1] == '.')) {
				cnt++;
			}
		}
		ans = max(ans, cnt);
		//cout << ans << endl;
	}

	for (i = 0; i < 4; i++) {
		int cnt = 0;
		for (j = 0; j < n; j++) {
			bool flag = true;
			for (k = 1; k < n - 1; k++) {
				if (s[i][k][j] == '#') {
					flag = false;
					break;
				}
			}
			if (flag && (s[i][0][j] == '.' || s[i][n - 1][j] == '.')) {
				cnt++;
			}
		}
		ans = max(ans, cnt);
		//cout << ans << endl;
	}

	for (i = 0; i < 4; i++) {
		int cnt = 0;
		bool flag = true;
		for (j = 0; j < n - 1; j++) {
			if (s[i][j][n - 1] == '#') {
				flag = false;
				break;
			}
		}
		if (flag) {
			cnt++;
			for (j = 0; j < n - 1; j++) {
				bool flag2 = true;
				for (k = 0; k < n - 1; k++) {
					if (s[i][k][j] == '#') {
						flag2 = false;
						break;
					}
				}
				if (flag2) {
					cnt++;
				}
			}
			bool flag3 = true;
			for (k = 1; k < n - 1; k++) {
				if (s[i][k][n - 1] == '#') {
					flag3 = false;
					break;
				}
			}
			if (flag3 && (s[i][0][n - 1] == '.' || s[i][n - 1][n - 1] == '.')) {
				cnt++;
			}
			ans = max(ans, cnt);
		}
		//cout << ans << endl;
	}
	for (i = 0; i < 4; i++) {
		int cnt = 0;
		bool flag = true;
		for (j = 0; j < n - 1; j++) {
			if (s[i][n - 1][j] == '#') {
				flag = false;
				break;
			}
		}
		if (flag) {
			cnt++;
			for (j = 0; j < n - 1; j++) {
				bool flag2 = true;
				for (k = 0; k < n - 1; k++) {
					if (s[i][j][k] == '#') {
						flag2 = false;
						break;
					}
				}
				if (flag2) {
					cnt++;
				}
			}
			bool flag3 = true;
			for (k = 1; k < n - 1; k++) {
				if (s[i][n - 1][k] == '#') {
					flag3 = false;
					break;
				}
			}
			if (flag3 && (s[i][n - 1][0] == '.' || s[i][n - 1][n - 1] == '.')) {
				cnt++;
			}
			ans = max(ans, cnt);
		}
		//cout << ans << endl;
	}
	cout << ans << endl;
}