#include <bits/stdc++.h>
using namespace std;
template <class C>
void mini(C& a4, C b4) {
  a4 = min(a4, b4);
}
template <class C>
void maxi(C& a4, C b4) {
  a4 = max(a4, b4);
}
template <typename T1, typename T2>
ostream& operator<<(ostream& out, pair<T1, T2> pair) {
  out << "(" << pair.first << ", " << pair.second << ")";
  return out;
}
const int N = 8;
string t[N];
bool p[N];
bool s[N];
int best = 16, curr = 0;
void check() {
  int add = 0;
  for (int i = 0; i < (N); ++i) {
    bool b = false, w = false;
    for (int j = 0; j < (N); ++j)
      if (!s[j]) {
        if (t[i][j] == 'B') {
          b = true;
        } else {
          w = true;
        }
      }
    if (b && w) return;
    if (b) ++add;
  }
  mini(best, curr + add);
}
void check(int k) {
  if (curr >= best) return;
  if (k == N) {
    check();
    return;
  }
  if (p[k]) {
    s[k] = true;
    ++curr;
    check(k + 1);
    s[k] = false;
    --curr;
  }
  check(k + 1);
}
int main() {
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(10);
  for (int i = 0; i < (N); ++i) {
    cin >> t[i];
  }
  for (int i = 0; i < (N); ++i) p[i] = true;
  for (int i = 0; i < (N); ++i)
    for (int j = 0; j < (N); ++j)
      if (t[j][i] == 'W') p[i] = false;
  check(0);
  cout << best << endl;
  return 0;
}
