#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  int n;
  cin >> n;
  vector<array<int, 2>> pts(n);
  for (int i = 0; i < n; i++) {
    string s;
    cin >> s;
    int x = 0;
    int y = 0;
    for (int j = 0; j < s.size(); j++) {
      if (s[j] == 'B')
        x++;
      else
        y++;
    }
    pts[i] = {x, y};
  }
  int a = 0;
  int b = 1000000;
  int res[2] = {0, 0};
  while (a < b) {
    int mid = (a + b) / 2;
    int hr[2] = {pts[0][0] - mid, pts[0][0] + mid};
    int vt[2] = {pts[0][1] - mid, pts[0][1] + mid};
    int dg[2] = {pts[0][0] - pts[0][1] - mid, pts[0][0] - pts[0][1] + mid};
    for (int i = 1; i < pts.size(); i++) {
      hr[0] = max(hr[0], pts[i][0] - mid);
      hr[1] = min(hr[1], pts[i][0] + mid);
      vt[0] = max(vt[0], pts[i][1] - mid);
      vt[1] = min(vt[1], pts[i][1] + mid);
      dg[0] = max(dg[0], pts[i][0] - pts[i][1] - mid);
      dg[1] = min(dg[1], pts[i][0] - pts[i][1] + mid);
    }
    bool ok = (vt[0] <= vt[1]) && (hr[0] <= hr[1]) && (dg[0] <= dg[1]) &&
              (dg[0] <= hr[1] - vt[0]) && (hr[0] - vt[1] <= dg[1]);
    if (ok) {
      b = mid;
      res[0] = hr[1];
      res[1] = vt[1];
      if (res[0] - res[1] < dg[0])
        res[1] -= dg[0] - (res[0] - res[1]);
      else if (dg[1] < res[0] - res[1])
        res[0] -= (res[0] - res[1]) - dg[1];
    } else {
      a = mid + 1;
    }
  }
  cout << a << endl;
  cout << string(res[0], 'B') + string(res[1], 'N') << endl;
  return 0;
}
