#include <bits/stdc++.h>
using namespace std;
template <typename A, typename B>
ostream& operator<<(ostream& cout, pair<A, B> const& p) {
  return cout << "(" << p.first << ", " << p.second << ")";
}
template <typename A>
ostream& operator<<(ostream& cout, vector<A> const& v) {
  cout << "[";
  for (int i = 0; i < v.size(); i++) {
    if (i) cout << ", ";
    cout << v[i];
  }
  return cout << "]";
}
void fast_io() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
}
void file_io(string taskname) {
  string fin = taskname + ".in";
  string fout = taskname + ".out";
  const char* FIN = fin.c_str();
  const char* FOUT = fout.c_str();
  freopen(FIN, "r", stdin);
  freopen(FOUT, "w", stdout);
  fast_io();
}
struct gem {
  int hor0, hor1, ver0, ver1, dia0, dia1;
  gem(int a, int b, int c, int d, int e, int first)
      : hor0(a), hor1(b), ver0(c), ver1(d), dia0(e), dia1(first) {}
  gem(int x, int y, int dist) {
    hor0 = x - dist;
    hor1 = x + dist;
    ver0 = y - dist;
    ver1 = y + dist;
    dia0 = y - x - dist;
    dia1 = y - x + dist;
  }
  gem merge(gem other) {
    int a = max(hor0, other.hor0);
    int b = min(hor1, other.hor1);
    int c = max(ver0, other.ver0);
    int d = min(ver1, other.ver1);
    int e = max(dia0, other.dia0);
    int first = min(dia1, other.dia1);
    return gem(a, b, c, d, e, first);
  }
  pair<int, int> valid() {
    vector<pair<int, int> > poss{
        {hor0, ver0},        {hor1, ver0},        {hor0, ver1},
        {hor1, ver1},        {hor0, dia0 + hor0}, {hor1, dia0 + hor1},
        {hor0, dia1 + hor0}, {hor1, dia1 + hor1}, {ver0 - dia0, ver0},
        {ver1 - dia0, ver1}, {ver0 - dia1, ver0}, {ver1 - dia1, ver1}};
    for (auto p : poss) {
      if (p.first >= 0 && p.second >= 0 && (p.second + p.first) > 0 &&
          p.first >= hor0 && p.first <= hor1 && p.second >= ver0 &&
          p.second <= ver1 && p.second - p.first >= dia0 &&
          p.second - p.first <= dia1) {
        return p;
      }
    }
    return make_pair(-1, -1);
  }
};
int main() {
  fast_io();
  int n;
  cin >> n;
  vector<pair<int, int> > v;
  for (int i = 0; i < (n); i++) {
    string second;
    cin >> second;
    int x = 0, y = 0;
    for (int i = 0; i < (second.size()); i++) {
      if (second.at(i) == 'B') x++;
      if (second.at(i) == 'N') y++;
    }
    v.push_back(make_pair(x, y));
  }
  pair<int, int> ans;
  int lo = 0;
  int hi = 500000;
  while (lo < hi) {
    int mid = (lo + hi) / 2;
    gem g(v[0].first, v[0].second, mid);
    for (int i = 1; i < n; i++) {
      gem h(v[i].first, v[i].second, mid);
      g = g.merge(h);
      if (g.valid().first < 0) {
        break;
      }
    }
    if (g.valid().first >= 0) {
      hi = mid;
      ans = g.valid();
    } else {
      lo = mid + 1;
    }
  }
  cout << lo << endl;
  for (int i = 0; i < (ans.first); i++) {
    cout << "B";
  }
  for (int i = 0; i < (ans.second); i++) {
    cout << "N";
  }
  cout << endl;
}
