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

int main() {
	int n;
	cin >> n;
	vector<string> ss(n);
	for(auto &&s : ss) {
		cin >> s;
	}
	int cnt = 0;
	int nana0 = 0, nana1 = 0;
	for(int i = 0; i < n; i++) {
		int tate = 0, yoko = 0;
		for(int j = 0; j < n; j++) {
			if(ss[i][j] == '.') tate++;
			else if(ss[i][j] == 'B') tate = -1e9;
			if(ss[j][i] == '.') yoko++;
			else if(ss[j][i] == 'B') yoko = -1e9;
		}
		if(tate == 1) cnt++;
		if(yoko == 1) cnt++;
		if(ss[i][i] == '.') nana0++;
		else if(ss[i][i] == 'B') nana0 = -1e9;
		if(ss[i][n-i-1] == '.') nana1++;
		else if(ss[i][n-i-1] == 'B') nana1 = -1e9;
	}
	if(nana0 == 1) cnt++;
	if(nana1 == 1) cnt++;
	cout << cnt << endl;
	return 0;
}