#include <bits/stdc++.h>
using namespace std;
const int Maxn = 500005;
int n;
char str[Maxn];
pair<int, int> p[Maxn];
pair<int, int> Get(int dif) {
  int Lx = 0, Rx = Maxn;
  int Ly = 0, Ry = Maxn;
  int Ld = -Maxn, Rd = Maxn;
  for (int i = 0; i < n; i++) {
    Lx = max(Lx, p[i].first - dif);
    Rx = min(Rx, p[i].first + dif);
    Ly = max(Ly, p[i].second - dif);
    Ry = min(Ry, p[i].second + dif);
    Ld = max(Ld, p[i].first - p[i].second - dif);
    Rd = min(Rd, p[i].first - p[i].second + dif);
  }
  for (int x = Lx; x <= Rx; x++) {
    int L = Ly, R = Ry;
    if (x == 0) L = max(L, 1);
    L = max(L, x - Rd);
    R = min(R, x - Ld);
    if (L <= R) return pair<int, int>(x, L);
  }
  return pair<int, int>(-1, -1);
}
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%s", str);
    int slen = strlen(str);
    for (int j = 0; j < slen; j++)
      if (str[j] == 'B')
        p[i].first++;
      else
        p[i].second++;
  }
  int lef = 0, rig = Maxn;
  while (lef <= rig) {
    int mid = lef + rig >> 1;
    if (Get(mid).first != -1)
      rig = mid - 1;
    else
      lef = mid + 1;
  }
  printf("%d\n", lef);
  pair<int, int> res = Get(lef);
  if (res.first) printf("%s", string(res.first, 'B').c_str());
  if (res.second) printf("%s", string(res.second, 'N').c_str());
  printf("\n");
  return 0;
}
