#include <bits/stdc++.h>
using namespace std;
const int maxn = 3e5 + 5, maxlen = 5e5 + 5;
const int inf = 3e6 + 5;
int n, x[maxn], y[maxn];
char s[maxlen];
int ansb, ansn;
bool check(int mid, int ty) {
  int xmin = 0, xmax = inf, ymin = 0, ymax = inf, dmin = -inf, dmax = inf;
  for (int i = 1; i <= n; i++) {
    xmin = max(xmin, x[i] - mid);
    xmax = min(xmax, x[i] + mid);
    ymin = max(ymin, y[i] - mid);
    ymax = min(ymax, y[i] + mid);
    dmin = max(dmin, x[i] - y[i] - mid);
    dmax = min(dmax, x[i] - y[i] + mid);
  }
  if (xmin > xmax || ymin > ymax || dmin > dmax) return 0;
  ymin = max(ymin, xmin - dmax);
  ymax = min(ymax, xmax - dmin);
  if (ymin > ymax) return 0;
  if (ty) {
    for (int x = xmin; x <= xmax; x++) {
      int rymin = max(ymin, x - dmax), rymax = min(ymax, x - dmin);
      if (rymin <= rymax && (x > 0 || rymax > 0)) {
        ansb = x, ansn = (x == 0) ? rymax : rymin;
        break;
      }
    }
  }
  return 1;
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%s", s + 1);
    int len = strlen(s + 1);
    for (int j = 1; j <= len; j++)
      if (s[j] == 'B')
        x[i]++;
      else
        y[i]++;
  }
  int l = 0, r = 2e6;
  while (l <= r) {
    int mid = (l + r) >> 1;
    if (check(mid, 0))
      r = mid - 1;
    else
      l = mid + 1;
  }
  printf("%d\n", ++r);
  check(r, 1);
  for (int i = 1; i <= ansb; i++) putchar('B');
  for (int i = 1; i <= ansn; i++) putchar('N');
  return 0;
}
