#include <bits/stdc++.h>
using namespace std;
const int N = 300000, M = 500000;
int xx[N], yy[N], n;
int x_, y_;
bool check(int d) {
  int xl = 0, xr = M;
  int yl = 0, yr = M;
  int xyl = -M, xyr = M;
  for (int i = 0; i < n; i++) {
    int x = xx[i], y = yy[i];
    xl = max(xl, x - d);
    xr = min(xr, x + d);
    yl = max(yl, y - d);
    yr = min(yr, y + d);
    xyl = max(xyl, x - y - d);
    xyr = min(xyr, x - y + d);
  }
  if (xl > xr || yl > yr || xyl > xyr) return false;
  int l = max(xl - yr, xyl), r = min(xr - yl, xyr);
  if (l > r) return false;
  if (yl <= xl - l)
    x_ = xl, y_ = xl - l;
  else
    x_ = yl + l, y_ = yl;
  return true;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n;
  for (int i = 0; i < n; i++) {
    string s;
    cin >> s;
    int m = s.length();
    for (int j = 0; j < m; j++) (s[j] == 'B' ? xx[i] : yy[i])++;
  }
  int lower = -1, upper = M;
  while (upper - lower > 1) {
    int d = (lower + upper) / 2;
    if (check(d))
      upper = d;
    else
      lower = d;
  }
  check(upper);
  if (x_ == 0 && y_ == 0) x_ = y_ = 1;
  cout << upper << '\n';
  cout << string(x_, 'B') + string(y_, 'N') << '\n';
  return 0;
}
