#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
const long long INF = 1e18;
long long N;
vector<pair<long long, long long> > IN[501000];
vector<pair<long long, long long> > v;
pair<long long, long long> f(long long border) {
  vector<long long> x;
  for (int i = 0; i < v.size(); i++) {
    x.push_back(v[i].first);
    x.push_back(v[i].first + border);
    if (v[i].first - border >= 0) x.push_back(v[i].first - border);
  }
  sort(x.begin(), x.end());
  x.erase(unique(x.begin(), x.end()), x.end());
  for (auto b : x) {
    long long maxi = 5e5;
    long long mini = 0;
    if (b == 0) mini = 1;
    for (auto tmp : v) {
      long long bnow = tmp.first;
      long long nnow = tmp.second;
      if (abs(bnow - b) > border) maxi = -1;
      if (b >= bnow) {
        long long delta = b - bnow;
        chmin(maxi, nnow + border);
        chmax(mini, nnow - (border - delta));
      } else {
        long long delta = bnow - b;
        chmax(mini, nnow - border);
        chmin(maxi, nnow + (border - delta));
      }
    }
    if (maxi >= mini) {
      return {b, mini};
    }
  }
  return {-1, -1};
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> N;
  for (int i = 0; i < N; i++) {
    long long A = 0;
    long long B = 0;
    string S;
    cin >> S;
    for (auto c : S) {
      if (c == 'B')
        B++;
      else
        A++;
    }
    IN[B].push_back({B, A});
  }
  for (int i = 0; i <= 5e5; i++) {
    if (IN[i].empty()) continue;
    if (IN[i].size() == 1) {
      v.push_back(IN[i][0]);
      continue;
    }
    sort(IN[i].begin(), IN[i].end());
    v.push_back(IN[i][0]);
    v.push_back(IN[i].back());
  }
  cerr << v.size() << "\n";
  long long ok = 5e5;
  long long ng = -1;
  while (abs(ok - ng) > 1) {
    long long mid = (ok + ng) / 2;
    auto tmp = f(mid);
    if (tmp.first == -1) {
      ng = mid;
    } else {
      ok = mid;
    }
  }
  auto ans = f(ok);
  cout << ok << "\n";
  for (int i = 0; i < ans.first; i++) cout << "B";
  for (int i = 0; i < ans.second; i++) cout << "N";
  cout << "\n";
  return 0;
}
