#include <bits/stdc++.h>
using namespace std;
template <class T>
ostream &operator<<(ostream &str, vector<T> &a) {
  for (auto &i : a) {
    str << i << " ";
  }
  return str;
}
template <class T>
istream &operator>>(istream &str, vector<T> &a) {
  for (auto &i : a) {
    str >> i;
  }
  return str;
}
template <class T>
ostream &operator<<(ostream &str, pair<T, T> &a) {
  str << a.first << " " << a.second;
  return str;
}
template <class T>
istream &operator>>(istream &str, pair<T, T> &a) {
  str >> a.first >> a.second;
  return str;
}
void solve();
signed main() {
  srand(time(0));
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cout.setf(ios::fixed);
  cout.precision(6);
  solve();
  return 0;
}
const long long MOD = 1e9 + 7, MAXN = 1e6 + 10, INF = 6e18 + 10, BASE = 37;
long long X, Y;
bool check(long long len, vector<pair<long long, long long> > &a) {
  long long x1 = -INF, x2 = INF, y1 = -INF, y2 = INF, b1 = -INF, b2 = INF;
  for (auto it : a) {
    x1 = max(x1, it.first - len);
    x2 = min(x2, it.first + len);
    y1 = max(y1, it.second - len);
    y2 = min(y2, it.second + len);
    b1 = max(b1, it.second - it.first - len);
    b2 = min(b2, it.second - it.first + len);
  }
  bool ok = true;
  if (x1 > x2) ok = false;
  if (y1 > y2) ok = false;
  if (b1 > b2) ok = false;
  if (ok) {
    long long B2 = (y2 - x1), B1 = (y1 - x2);
    long long l = max(B1, b1), r = min(b2, B2);
    if (l > r) {
      ok = false;
    } else {
      long long k = y2 - x2;
      if (r <= k) {
        X = x2, Y = x2 + r;
      } else if (l > k) {
        X = y2 - l, Y = y2;
      } else {
        X = x2, Y = y2;
      }
      if (X == 0 && Y == 0) {
        ok = false;
      }
    }
  }
  return ok;
}
void solve() {
  long long n;
  cin >> n;
  vector<pair<long long, long long> > a;
  for (long long i = 0; i < n; ++i) {
    long long c = 0;
    string s;
    cin >> s;
    for (auto it : s) {
      if (it == 'B') {
        c++;
      }
    }
    a.push_back({c, (long long)((s).size()) - c});
  }
  long long l = -1, r = 1e9 + 10;
  while (r - l > 1) {
    long long mid = (r + l) / 2;
    if (check(mid, a)) {
      r = mid;
    } else {
      l = mid;
    }
  }
  check(r, a);
  cout << r << '\n';
  for (long long i = 0; i < X; ++i) {
    cout << 'B';
  }
  for (long long i = 0; i < Y; ++i) {
    cout << 'N';
  }
  cout << '\n';
}
