#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const int inf = (1 << 30) - 1;
const ll INF = (1LL << 60) - 1;
const double pi = acos(-1.0);
const double EPS = 1e-10;
template <typename T>
bool chmax(T &x, const T &y) {
  if (x < y) {
    x = y;
    return true;
  }
  return false;
}
template <typename T>
bool chmin(T &x, const T &y) {
  if (x > y) {
    x = y;
    return true;
  }
  return false;
}
void in() {}
template <typename Head, typename... Tail>
void in(Head &&head, Tail &&...tail) {
  cin >> head;
  in(forward<Tail>(tail)...);
}
void out() { cout << '\n'; }
template <typename Head, typename... Tail>
void out(Head &&head, Tail &&...tail) {
  cout << head << ' ';
  out(forward<Tail>(tail)...);
}
void outn() {}
template <typename Head, typename... Tail>
void outn(Head &&head, Tail &&...tail) {
  cout << head << '\n';
  outn(forward<Tail>(tail)...);
}
template <typename T, typename U>
void in(pair<T, U> &p) {
  cin >> p.first >> p.second;
}
template <typename T, typename U>
void out(pair<T, U> p) {
  cout << p.first << ' ' << p.second << '\n';
}
using vi = vector<int>;
using vll = vector<ll>;
template <typename T>
void vin(vector<T> &a) {
  for (int i = 0; i < (int)a.size(); i++) cin >> a[i];
}
template <typename T>
void vout(const vector<T> &a) {
  for (auto &e : a) cout << e << ' ';
  cout << '\n';
}
template <typename T>
void voutn(const vector<T> &a) {
  for (auto &e : a) cout << e << '\n';
}
template <typename T>
void unique(vector<T> &a) {
  sort(a.begin(), a.end()), a.erase(unique(a.begin(), a.end()), a.end());
}
vector<int> iota(int n) {
  vector<int> ret(n);
  iota(ret.begin(), ret.end(), 0);
  return ret;
}
template <typename T>
vector<int> iota(const vector<T> &a, bool greater = false) {
  vector<int> ret = iota((int)a.size());
  sort(ret.begin(), ret.end(),
       [&](int i, int j) { return (a[i] < a[j]) ^ greater; });
  return ret;
}
struct io_setup {
  io_setup() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout << fixed << setprecision(15);
  }
} io_setup;
const int MOD = 1000000007;
void solve(int a, int b) {
  if (a == 0 && b == 0)
    out("BN");
  else
    out(string(a, 'B') + string(b, 'N'));
}
int main() {
  int N;
  in(N);
  vector<string> S(N);
  vin(S);
  int l = -1, r = inf;
  vi x(N, 0), y(N, 0);
  int mc = inf, Mc = -inf;
  int mx = inf, Mx = -inf, my = inf, My = -inf;
  for (int i = 0; i < N; i++) {
    for (auto &e : S[i]) (e == 'B' ? x : y)[i]++;
    chmin(mc, x[i] - y[i]), chmax(Mc, x[i] - y[i]);
    chmin(mx, x[i]), chmax(Mx, x[i]), chmin(my, y[i]), chmax(My, y[i]);
  }
  while (r - l > 1) {
    int m = (l + r) / 2;
    int lc = Mc - m, rc = mc + m;
    int lx = Mx - m, rx = mx + m, ly = My - m, ry = my + m;
    if (lx > rx || ly > ry || lc > rc) {
      l = m;
      continue;
    }
    int a = lx - ry, b = rx - ly;
    if (rc < a || lc > b)
      l = m;
    else
      r = m;
  }
  out(r);
  int lc = Mc - r, rc = mc + r;
  int lx = Mx - r, rx = mx + r, ly = My - r, ry = my + r;
  int a = lx - ry, b = rx - ly;
  if (a >= lc)
    solve(lx, ry);
  else if (b <= rc)
    solve(rx, ly);
  else {
    int d = lc - a;
    if (d <= ry - ly)
      solve(lx, ry - d);
    else
      solve(lx + d - (ry - ly), ly);
  }
}
