#include <bits/stdc++.h>
using namespace std;
const int mod = (int)1e9 + 7;
const int N = (int)5e5 + 7;
char s[N];
pair<int, int> st[N];
int n;
bool sol(int mid) {
  int lb = 0, rb = N, bb = 0, tb = N;
  int l1 = -2 * N, l2 = 2 * N;
  for (int i = 1; i <= n; i++) {
    int v1 = st[i].first, v2 = st[i].second;
    lb = max(lb, v1 - mid);
    bb = max(bb, v2 - mid);
    rb = min(rb, v1 + mid);
    tb = min(tb, v2 + mid);
    l1 = max(l1, v1 - v2 - mid);
    l2 = min(l2, v1 - v2 + mid);
    l1 = max(l1, lb - tb);
    l2 = min(l2, rb - bb);
  }
  if (lb <= rb && bb <= tb && l1 <= l2) {
    return true;
  } else {
    return false;
  }
}
char ot[N * 4];
void build(int mid) {
  int lb = 0, rb = N, bb = 0, tb = N;
  int l1 = -2 * N, l2 = 2 * N;
  for (int i = 1; i <= n; i++) {
    int v1 = st[i].first, v2 = st[i].second;
    lb = max(lb, v1 - mid);
    bb = max(bb, v2 - mid);
    rb = min(rb, v1 + mid);
    tb = min(tb, v2 + mid);
    l1 = max(l1, v1 - v2 - mid);
    l2 = min(l2, v1 - v2 + mid);
    l1 = max(l1, lb - tb);
    l2 = min(l2, rb - bb);
  }
  int cntp = 0;
  for (int i = lb; i <= rb; i++) {
    int x = i;
    int ll = bb, rr = tb;
    rr = min(rr, i - l1);
    ll = max(ll, i - l2);
    if (ll <= rr) {
      int y = rr;
      if (!x && !y) continue;
      for (int j = 0; j < x; j++) ot[++cntp] = 'B';
      for (int j = 0; j < y; j++) ot[++cntp] = 'N';
      printf("%d\n", mid);
      printf("%s\n", ot + 1);
      exit(0);
    }
  }
  build(mid + 1);
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    int v1 = 0, v2 = 0;
    scanf("%s", s + 1);
    int l = strlen(s + 1);
    for (int j = 1; j <= l; j++) {
      if (s[j] == 'B')
        v1++;
      else
        v2++;
    }
    st[i] = {v1, v2};
  }
  int ll = 0, rr = N, ans = rr;
  while (ll <= rr) {
    int mid = (ll + rr) >> 1;
    if (sol(mid)) {
      rr = mid - 1;
      ans = mid;
    } else {
      ll = mid + 1;
    }
  }
  sol(ans);
  build(ans);
  return 0;
}
