#include <bits/stdc++.h>
using namespace std;
template <class T, class U>
bool cmax(T& a, const U& b) {
  return a < b ? a = b, 1 : 0;
}
template <class T, class U>
bool cmin(T& a, const U& b) {
  return b < a ? a = b, 1 : 0;
}
void _BG(const char* s) { cerr << s << endl; }
template <class T, class... TT>
void _BG(const char* s, T a, TT... b) {
  for (size_t c = 0; *s && (c || *s != ','); cerr << *s++)
    c += count(begin("([{"), end("([{"), *s) -
         count(begin(")]}"), end(")]}"), *s);
  cerr << " = " << a;
  if (*s) {
    cerr << ", ";
    ++s;
  }
  _BG(s, b...);
}
const int inf = 1e7;
struct pos {
  int xl, xr;
  int yl, yr;
  int xyl, xyr;
  pair<int, int> ans;
  pos() {}
  pos(int a, int b, int c, int d, int e, int f)
      : xl(a), xr(b), yl(c), yr(d), xyl(e), xyr(f) {}
  pos operator+(const pos& r) const {
    return pos(max(xl, r.xl), min(xr, r.xr), max(yl, r.yl), min(yr, r.yr),
               max(xyl, r.xyl), min(xyr, r.xyr));
  }
  bool ok() {
    if (xl > xr || yl > yr || xyl > xyr) return 0;
    for (int x : {xl, xr}) {
      int l = max(yl, x - xyr);
      int r = min(yr, x - xyl);
      if (l <= r) {
        ans = {x, l};
        return 1;
      }
    }
    for (int y : {yl, yr}) {
      int l = max(xl, y + xyl);
      int r = min(xr, y + xyr);
      if (l <= r) {
        ans = {l, y};
        return 1;
      }
    }
    return 0;
  }
};
int n;
vector<pair<int, int> > p;
pos va, vb;
bool ok(int d) {
  va = pos(1, inf, 0, inf, -inf, inf);
  vb = pos(0, inf, 1, inf, -inf, inf);
  for (auto [x, y] : p) {
    pos t(x - d, x + d, y - d, y + d, x - y - d, x - y + d);
    va = va + t;
    vb = vb + t;
  }
  return va.ok() || vb.ok();
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> n;
  for (int i = 0; i < n; ++i) {
    string s;
    cin >> s;
    int x = 0, y = 0;
    for (char c : s)
      if (c == 'B')
        ++x;
      else
        ++y;
    p.emplace_back(x, y);
  }
  int lo = 0, hi = 1e7;
  while (lo <= hi) {
    int mi = (lo + hi) / 2;
    if (ok(mi))
      hi = mi - 1;
    else
      lo = mi + 1;
  }
  assert(ok(lo));
  cout << lo << endl;
  auto a = va.ok() ? va.ans : (vb.ok(), vb.ans);
  for (int i = 0; i < a.first; ++i) cout << 'B';
  for (int i = 0; i < a.second; ++i) cout << 'N';
  cout << endl;
}
