#include <bits/stdc++.h>
using namespace std;
template <typename _T>
inline void read(_T &f) {
  f = 0;
  _T fu = 1;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') {
      fu = -1;
    }
    c = getchar();
  }
  while (c >= '0' && c <= '9') {
    f = (f << 3) + (f << 1) + (c & 15);
    c = getchar();
  }
  f *= fu;
}
template <typename T>
void print(T x) {
  if (x < 0) putchar('-'), x = -x;
  if (x < 10)
    putchar(x + 48);
  else
    print(x / 10), putchar(x % 10 + 48);
}
template <typename T>
void print(T x, char t) {
  print(x);
  putchar(t);
}
const int N = 5e5 + 5, INF = 0x7fffffff;
struct ele {
  int a, b;
  ele(int x = 0, int y = 0) : a(x), b(y) {}
} a[N];
char c[N];
int n, lx, rx, ly, ry;
int main() {
  read(n);
  for (int i = 1; i <= n; i++) {
    scanf("%s", c + 1);
    int len = strlen(c + 1);
    for (int j = 1; j <= len; j++) {
      if (c[j] == 'B')
        ++a[i].a;
      else
        ++a[i].b;
    }
  }
  int l = 0, r = 500000, ans = -1, ansx, ansy;
  while (l <= r) {
    int mid = (l + r) >> 1, lim1 = -INF, lim2 = INF;
    lx = ly = -INF;
    rx = ry = INF;
    for (int i = 1; i <= n; i++) {
      lx = max(lx, a[i].a - mid);
      rx = min(rx, a[i].a + mid);
      ly = max(ly, a[i].b - mid);
      ry = min(ry, a[i].b + mid);
      lim1 = max(lim1, a[i].a - a[i].b - mid);
      lim2 = min(lim2, a[i].a - a[i].b + mid);
    }
    lim1 = max(lim1, lx - ry);
    lim2 = min(lim2, rx - ly);
    if (lx <= rx && ly <= ry && lim1 <= lim2) {
      int tmp = rx - ry;
      lim1 = max(lim1, min(lim2, tmp));
      lim2 = min(lim2, max(lim1, tmp));
      if (rx - lim1 <= ry && rx >= 0 && rx - lim1 >= 0) {
        ansx = rx;
        ansy = rx - lim1;
        ans = mid;
        r = mid - 1;
        continue;
      } else if (lim2 + ry >= 0 && ry >= 0) {
        ansx = lim2 + ry;
        ansy = ry;
        ans = mid;
        r = mid - 1;
        continue;
      }
    }
    l = mid + 1;
  }
  print(ans, '\n');
  for (int i = 1; i <= ansx; i++) putchar('B');
  for (int i = 1; i <= ansy; i++) putchar('N');
  putchar('\n');
  return 0;
}
