#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 5;
int n, ansx, ansy;
char s[N];
pair<int, int> p[N];
bool ck(int d) {
  int up, dn, lf, rt, b1, b2;
  b1 = up = rt = 1e7, b2 = -1e7, dn = lf = 0;
  for (int i = (1); i < (n + 1); i++) {
    int x = p[i].first, y = p[i].second;
    up = min(up, y + d);
    dn = max(dn, y - d);
    lf = max(lf, x - d);
    rt = min(rt, x + d);
    b1 = min(b1, y - x + d);
    b2 = max(b2, y - x - d);
  }
  if (up < dn || rt < lf || b1 < b2) return false;
  if (up - lf < b2 || dn - rt > b1) return false;
  if (b1 >= up - lf)
    ansx = lf, ansy = up;
  else if (b2 <= dn - rt)
    ansx = rt, ansy = dn;
  else {
    ansx = rt;
    ansy = rt + b1;
    if (ansy > up) {
      ansy = up;
      ansx = up - b1;
    }
  }
  return true;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  for (int i = (1); i < (n + 1); i++) {
    cin >> s;
    int x = 0, y = 0, len = strlen(s);
    for (int j = (0); j < (len); j++)
      if (s[j] == 'B')
        x++;
      else
        y++;
    p[i] = pair<int, int>(x, y);
  }
  int ans = -1, L = 0, R = 1e6;
  while (L <= R) {
    int mid = L + R >> 1;
    if (ck(mid)) {
      R = mid - 1;
      ans = mid;
    } else
      L = mid + 1;
  }
  cout << ans << "\n";
  for (int i = (1); i < (ansx + 1); i++) cout << "B";
  for (int i = (1); i < (ansy + 1); i++) cout << "N";
  return 0;
}
