#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
// constexpr int MOD = 1000000007;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

bool is_valid(const string& s) {
  return ranges::count(s, '.') == 1 && ranges::count(s, 'B') == 0;
}

int main() {
  int n; cin >> n;
  vector<string> s(n);
  for (string& s_i : s) cin >> s_i;
  int ans = 0;
  for (const string& s_i : s) ans += is_valid(s_i);
  REP(j, n) {
    string t = "";
    REP(i, n) t += s[i][j];
    ans += is_valid(t);
  }
  string diag = "";
  REP(i, n) diag += s[i][i];
  ans += is_valid(diag);
  diag = "";
  REP(i, n) diag += s[i][n - i - 1];
  ans += is_valid(diag);
  cout << ans << '\n';
  return 0;
}