#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 7;
vector<pair<int, int>> v;
pair<int, int> check(int d) {
  int l = 0, r = N - 1, uu = N - 1, dd = 0, nu = 10 * N, nd = -10 * N;
  for (int i = 0; i < (int)v.size(); i++) {
    auto [x, y] = v[i];
    l = max(l, x - d);
    r = min(r, x + d);
    dd = max(dd, y - d);
    uu = min(uu, y + d);
    nu = min(nu, y + d - x);
    nd = max(nd, y - d - x);
  }
  if (l > r || dd > uu) return {-1, -1};
  for (int x = l; x <= r; x++) {
    int curd = max(dd, nd + x);
    int curu = min(uu, nu + x);
    if (curd <= curu && (x != 0 || curu != 0)) return {x, curu};
  }
  return {-1, -1};
}
signed main() {
  ios_base ::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    string s;
    cin >> s;
    int a = 0, b = 0;
    for (int j = 0; j < (int)s.length(); j++) {
      if (s[j] == 'N')
        a++;
      else
        b++;
    }
    v.push_back({a, b});
  }
  int l = -1, r = 2 * N, mid;
  pair<int, int> res;
  while (r - l > 1) {
    mid = (l + r) / 2;
    auto kek = check(mid);
    if (kek.first != -1) {
      res = kek;
      r = mid;
    } else {
      l = mid;
    }
  }
  cout << r << endl;
  for (int i = 0; i < res.first; i++) cout << "N";
  for (int i = 0; i < res.second; i++) cout << "B";
}
