#include <bits/stdc++.h>
using namespace std;
using UL = unsigned int;
using ULL = unsigned long long;
using LL = long long;
int N;
int CB[300000];
int CN[300000];
int Bbuf = 0, Nbuf = 0;
int F(int cn, int cb) {
  int ans = 0;
  for (int i = 0; i < (N); i++) {
    ans = max(ans, abs(cn - CN[i]));
    ans = max(ans, abs(cb - CB[i]));
    ans = max(ans, abs((cn - CN[i]) - (cb - CB[i])));
  }
  return ans;
}
int FF(int cb) {
  int lN, rN;
  lN = -1;
  rN = 500010;
  if (cb == 0) lN = 0;
  while (lN + 2 < rN) {
    int m1N = (lN + lN + rN) / 3, m2N = (lN + rN + rN) / 3;
    if (F(m1N, cb) < F(m2N, cb))
      rN = m2N;
    else
      lN = m1N;
  }
  Nbuf = lN + 1;
  return F(Nbuf, cb);
}
int main() {
  cin >> N;
  for (int i = 0; i < (N); i++) {
    CB[i] = CN[i] = 0;
    string S;
    cin >> S;
    for (char c : S)
      if (c == 'B')
        CB[i]++;
      else if (c == 'N')
        CN[i]++;
  }
  int lB, rB;
  lB = -1;
  rB = 500010;
  while (lB + 2 < rB) {
    int m1B = (lB + lB + rB) / 3, m2B = (lB + rB + rB) / 3;
    if (FF(m1B) < FF(m2B))
      rB = m2B;
    else
      lB = m1B;
  }
  Bbuf = lB + 1;
  FF(Bbuf);
  printf("%d\n", F(Nbuf, Bbuf));
  for (int i = 0; i < (Bbuf); i++) printf("B");
  for (int i = 0; i < (Nbuf); i++) printf("N");
  printf("\n");
  return 0;
}
