#include <bits/stdc++.h>
using namespace std;
template <class T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  os << "\n[";
  for (const T &first : v) os << first << ',';
  return os << "]\n";
}
namespace std {
template <class T1, class T2>
struct hash<pair<T1, T2>> {
 public:
  size_t operator()(const pair<T1, T2> &p) const {
    size_t first = hash<T1>()(p.first), second = hash<T2>()(p.second);
    return first ^ (second + 0x9e3779b9 + (first << 6) + (first >> 2));
  }
};
}  // namespace std
int n;
vector<pair<long long, long long>> pts;
vector<long long> xs, ys;
int xlo, xhi, ylo, yhi;
int dist(int dx, int dy) {
  if (dx >= 0 && dy >= 0) return max(dx, dy);
  if (dx <= 0 && dy <= 0) return max(-dx, -dy);
  return abs(dx) + abs(dy);
}
int maxd(int first, int second) {
  int res = 0;
  for (auto [u, v] : pts) res = max(res, dist(first - u, second - v));
  return res;
}
int f(int first) {
  int A = ylo, B = yhi;
  while (B - A > 10) {
    int miL = (2 * A + B) / 3;
    int miR = (A + 2 * B) / 3;
    if (maxd(first, miL) < maxd(first, miR))
      B = miR;
    else
      A = miL;
  }
  int retVal = INT_MAX;
  for (int second = A; second <= B; second++) {
    int res = maxd(first, second);
    if (res <= retVal) {
      retVal = res;
    }
  }
  return retVal;
}
pair<long long, long long> minim(int first) {
  int A = ylo, B = yhi;
  while (B - A > 10) {
    int miL = (2 * A + B) / 3;
    int miR = (A + 2 * B) / 3;
    if (maxd(first, miL) < maxd(first, miR))
      B = miR;
    else
      A = miL;
  }
  int retVal = INT_MAX;
  int rety = -1;
  for (int second = A; second <= B; second++) {
    int res = maxd(first, second);
    if (res <= retVal) {
      retVal = res;
      rety = second;
    }
  }
  return {retVal, rety};
}
void run() {
  cin >> n;
  for (auto i = (0); i < (n); ++i) {
    string S;
    cin >> S;
    int na = 0, nb = 0;
    for (char ch : S) (ch == 'B' ? na : nb)++;
    pts.emplace_back(na, nb);
    xs.push_back(na);
    ys.push_back(nb);
  }
  xlo = *min_element(begin(xs), end(xs));
  xhi = *max_element(begin(xs), end(xs));
  ylo = *min_element(begin(ys), end(ys));
  yhi = *max_element(begin(ys), end(ys));
  int A = xlo, B = xhi;
  while (B - A > 10) {
    int miL = (2 * A + B) / 3;
    int miR = (A + 2 * B) / 3;
    if (f(miL) < f(miR))
      B = miR;
    else
      A = miL;
  }
  int retVal = INT_MAX;
  int retx = -1;
  for (int first = A; first <= B; first++) {
    int res = f(first);
    if (res <= retVal) {
      retVal = res;
      retx = first;
    }
  }
  auto [D, rety] = minim(retx);
  cout << D << endl;
  for (auto i = (0); i < (retx); ++i) cout << 'B';
  for (auto i = (0); i < (rety); ++i) cout << 'N';
  cout << endl;
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout << fixed << setprecision(20);
  run();
  return 0;
}
