#include <bits/stdc++.h>
using namespace std;
template <class T>
using vc = vector<T>;
template <class T>
using vvc = vc<vc<T>>;
template <class T>
void mkuni(vector<T>& v) {
  sort(v.begin(), v.end());
  v.erase(unique(v.begin(), v.end()), v.end());
}
long long rand_int(long long l, long long r) {
  static mt19937_64 gen(chrono::steady_clock::now().time_since_epoch().count());
  return uniform_int_distribution<long long>(l, r)(gen);
}
template <class T>
void print(T x, int suc = 1) {
  cout << x;
  if (suc == 1)
    cout << '\n';
  else
    cout << ' ';
}
template <class T>
void print(const vector<T>& v, int suc = 1) {
  for (int i = 0; i < v.size(); i++)
    print(v[i], i == (int)(v.size()) - 1 ? suc : 2);
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n;
  cin >> n;
  vc<string> s(n);
  for (int i = 0; i < n; i++) cin >> s[i];
  vc<pair<int, int>> p(n);
  for (int i = 0; i < n; i++) {
    for (auto c : s[i]) {
      if (c == 'B')
        p[i].first++;
      else
        p[i].second++;
    }
  }
  auto getdis = [&](int c1, int c2, int y1, int y2) {
    if (c1 >= y1 && c2 >= y2) return max(c1 - y1, c2 - y2);
    if (c1 <= y1 && c2 <= y2) return max(y1 - c1, y2 - c2);
    return abs(c1 - y1) + abs(c2 - y2);
  };
  auto getv = [&](int c1, int c2) {
    int ret = 0;
    for (int i = 0; i < n; i++)
      ret = max(ret, getdis(c1, c2, p[i].first, p[i].second));
    return ret;
  };
  auto solve = [&](int x) {
    int L = 0, R = 5e5 + 7;
    while (L < R) {
      int len = (R - L) / 3;
      int l = L + len, r = R - len;
      int cl = getv(x, l), cr = getv(x, r);
      if (cl < cr)
        R = r - 1;
      else
        L = l + 1;
    }
    return make_pair(L, getv(x, L));
  };
  int L = 0, R = 5e5 + 7;
  while (L < R) {
    int len = (R - L) / 3;
    int l = L + len, r = R - len;
    auto lp = solve(l), rp = solve(r);
    if (lp.second < rp.second)
      R = r - 1;
    else
      L = l + 1;
  }
  auto ans = solve(L);
  print(ans.second);
  string op;
  for (int i = 0; i < L; i++) op += 'B';
  for (int i = 0; i < ans.first; i++) op += 'N';
  cout << op << '\n';
}
