#include <bits/stdc++.h>
using namespace std;
const int maxn = 5e5 + 5;
const int P = 998244353;
const int inf = 0x3f3f3f3f;
int n, ans;
pair<int, int> a[maxn], L[maxn], ANS;
pair<pair<int, int>, pair<int, int>> p[maxn];
char s[maxn];
inline int read() {
  char ch = getchar();
  int u = 0, f = 1;
  while (!isdigit(ch)) {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (isdigit(ch)) {
    u = u * 10 + ch - 48;
    ch = getchar();
  }
  return u * f;
}
inline pair<pair<int, int>, pair<int, int>> AND(
    pair<pair<int, int>, pair<int, int>> a,
    pair<pair<int, int>, pair<int, int>> b) {
  return make_pair(make_pair(max(a.first.first, b.first.first),
                             max(a.first.second, b.first.second)),
                   make_pair(min(a.second.first, b.second.first),
                             min(a.second.second, b.second.second)));
}
inline bool is(pair<pair<int, int>, pair<int, int>> a,
               pair<pair<int, int>, pair<int, int>> b) {
  if (b.second.first < a.first.first || b.second.second < a.first.second ||
      b.first.first > a.second.first || b.first.second > b.second.second)
    return false;
  return true;
}
inline void print(pair<pair<int, int>, pair<int, int>> a) {
  cout << a.first.first << " " << a.first.second << " " << a.second.first << " "
       << a.second.second << endl;
}
inline bool check(int x) {
  pair<pair<int, int>, pair<int, int>> tmp =
      make_pair(make_pair(0, 0), make_pair(inf, inf));
  pair<int, int> tmpL = make_pair(-inf, inf);
  for (int i = 1; i <= n; ++i) {
    p[i].second.first = a[i].first + x;
    p[i].second.second = a[i].second + x;
    p[i].first.first = a[i].first - x;
    p[i].first.second = a[i].second - x;
    L[i].first = a[i].second - a[i].first - x;
    L[i].second = a[i].second - a[i].first + x;
    tmp = AND(tmp, p[i]);
    tmpL.first = max(tmpL.first, L[i].first);
    tmpL.second = min(tmpL.second, L[i].second);
  }
  if (tmpL.first > tmpL.second || tmp.first.first > tmp.second.first ||
      tmp.first.second > tmp.second.second ||
      tmp.first.second - tmp.second.first > tmpL.second ||
      tmp.second.second - tmp.first.first < tmpL.first)
    return false;
  if (tmp.second.second - tmp.second.first < tmpL.first) {
    ANS.second = tmp.second.second;
    ANS.first = tmp.second.second - tmpL.first;
  } else if (tmp.second.second - tmp.second.first > tmpL.second) {
    ANS.first = tmp.second.first;
    ANS.second = tmp.second.first + tmpL.second;
  } else
    ANS = tmp.second;
  return true;
}
int main() {
  n = read();
  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')
        a[i].first++;
      else
        a[i].second++;
    }
  }
  int l = 0, r = 1e6;
  while (l <= r) {
    int mid = l + r >> 1;
    if (check(mid))
      r = mid - 1, ans = mid;
    else
      l = mid + 1;
  }
  cout << ans << endl;
  for (int i = 1; i <= ANS.first; ++i) putchar('B');
  for (int i = 1; i <= ANS.second; ++i) putchar('N');
  cout << endl;
  return 0;
}
