#include <bits/stdc++.h>
using namespace std;
vector<string> s(3e5 + 1);
vector<pair<int, int>> p;
int n;
vector<pair<int, int>> q;
int Kr(int kb, int kn) {
  int ans = 0;
  for (int i = 0; i < n; i++) {
    int r1 = q[i].first - kb;
    int r2 = q[i].second - kn;
    int r;
    if (r1 * r2 >= 0)
      r = max(abs(r1), abs(r2));
    else
      r = abs(r1) + abs(r2);
    ans = max(ans, r);
  }
  return ans;
}
pair<int, int> F(int kb) {
  int Fl = 0, Fr = 5e5;
  if (!kb) Fl++;
  while (Fr - Fl > 2) {
    int m1 = Fl + (Fr - Fl) / 3;
    int m2 = Fr - (Fr - Fl) / 3;
    if (Kr(kb, m1) >= Kr(kb, m2))
      Fl = m1;
    else
      Fr = m2;
  }
  return min(make_pair(Kr(kb, Fl), Fl), min(make_pair(Kr(kb, Fl + 1), Fl + 1),
                                            make_pair(Kr(kb, Fl + 2), Fl + 2)));
}
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> s[i];
  }
  q.resize(n);
  for (int i = 0; i < n; i++) {
    int kb = 0;
    for (int j = 0; j < s[i].size(); j++) {
      if (s[i][j] == 'B') ++kb;
    }
    q[i] = {kb, s[i].size() - kb};
  }
  int l = 0, r = 5e5;
  while (r - l > 2) {
    int m1 = l + (r - l) / 3;
    int m2 = r - (r - l) / 3;
    if (F(m1) >= F(m2))
      l = m1;
    else
      r = m2;
  }
  auto l0 = F(l);
  auto l1 = F(l + 1);
  auto l2 = F(l + 2);
  if (l0 <= l1 && l0 <= l2) {
    cout << l0.first << "\n";
    for (int i = 0; i < l; i++) {
      cout << "B";
    }
    for (int i = 0; i < l0.second; i++) {
      cout << "N";
    }
  } else if (l1 <= l0 && l1 <= l2) {
    cout << l1.first << "\n";
    for (int i = 0; i < l + 1; i++) {
      cout << "B";
    }
    for (int i = 0; i < l1.second; i++) {
      cout << "N";
    }
  } else {
    cout << l2.first << "\n";
    for (int i = 0; i < l + 2; i++) {
      cout << "B";
    }
    for (int i = 0; i < l2.second; i++) {
      cout << "N";
    }
  }
}
