#include <bits/stdc++.h>
using namespace std;
using namespace std;
const int maxn = 300000 + 10;
const int inf = 1000000000;
string s[maxn];
int n;
pair<int, int> p[maxn];
int x[2], y[2], d[2];
pair<int, int> ansp;
inline int judge(int r) {
  x[0] = -inf, x[1] = inf;
  y[0] = -inf, y[1] = inf;
  d[0] = -inf, d[1] = inf;
  for (auto i = (1); i <= (n); ++i) {
    pair<int, int>& e = p[i];
    x[0] = max(x[0], e.first - r);
    x[1] = min(x[1], e.first + r);
    y[0] = max(y[0], e.second - r);
    y[1] = min(y[1], e.second + r);
    d[0] = max(d[0], e.second - e.first - r);
    d[1] = min(d[1], e.second - e.first + r);
  }
  for (auto px = (x[0]); px <= (x[1]); ++px) {
    int l, r;
    l = max(y[0], px + d[0]);
    r = min(y[1], px + d[1]);
    if (r >= l && r >= 0) {
      if (px + r == 0) continue;
      ansp = {px, r};
      return 1;
    }
  }
  return 0;
}
inline void solve() {
  int l, r;
  l = 0, r = 500010;
  while (l < r) {
    int mid = r - (r - l + 1) / 2;
    if (judge(mid))
      r = mid;
    else
      l = mid + 1;
  }
  judge(l);
  cout << l << endl;
  cout << string(ansp.first, 'B') << string(ansp.second, 'N') << endl;
}
int main(void) {
  ios::sync_with_stdio(0);
  cout.tie(0);
  cin.tie(0);
  ;
  cin >> n;
  for (auto i = (1); i <= (n); ++i) {
    cin >> s[i];
    pair<int, int>& e = p[i];
    e = {0, 0};
    for (auto c : s[i]) {
      if (c == 'B')
        e.first++;
      else
        e.second++;
    }
  }
  solve();
  return 0;
}
