#include <bits/stdc++.h>
using namespace std;
const int N = 5e5 + 100;
int n;
char s[N];
vector<pair<int, int>> q;
int LX, RX, LY, RY, BUP, BDOWN, xx, yy;
void umax(int &a, int b) { a = max(a, b); }
void umin(int &a, int b) { a = min(a, b); }
bool check(int x, int y) {
  if (x < 0 || y < 0) return false;
  if (x == 0 && y == 0) return false;
  if (x < LX || RX < x) return false;
  if (y < LY || RY < y) return false;
  if (!(x + BUP >= y) || !(x + BDOWN <= y)) return false;
  xx = x;
  yy = y;
  return true;
}
bool solve(int d) {
  LX = LY = 0;
  RX = RY = 1e9;
  BUP = 1e9;
  BDOWN = -1e9;
  for (auto it : q) {
    int x = it.first, y = it.second;
    umin(RX, x + d);
    umax(LX, x - d);
    umin(RY, y + d);
    umax(LY, y - d);
    int z = x - d;
    int f = y - z;
    umin(BUP, f);
    z = x + d;
    f = y - z;
    umax(BDOWN, f);
  }
  for (int i = 0; i <= 1; ++i)
    for (int j = 0; j <= 1; ++j)
      if (check(i, j)) return true;
  if (check(LX, LY)) return true;
  if (check(LX, RY)) return true;
  if (check(RX, LY)) return true;
  if (check(RX, RY)) return true;
  if (check(LX, LX + BUP)) return true;
  if (check(LX, LX + BDOWN)) return true;
  if (check(RX, RX + BUP)) return true;
  if (check(RX, RX + BDOWN)) return true;
  if (check(LY - BUP, LY)) return true;
  if (check(LY - BDOWN, LY)) return true;
  if (check(RY - BUP, RY)) return true;
  if (check(RY - BDOWN, RY)) return true;
  return false;
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) {
    scanf("%s", s + 1);
    int m = strlen(s + 1), a = 0, b = 0;
    for (int j = 1; j <= m; ++j) (s[j] == 'B' ? a : b) += 1;
    q.push_back({a, b});
  }
  int l = 0, r = 1e6;
  while (l < r) {
    int m = (l + r) / 2;
    if (solve(m))
      r = m;
    else
      l = m + 1;
  }
  solve(l);
  printf("%d\n", l);
  for (int i = 1; i <= xx; ++i) printf("B");
  for (int i = 1; i <= yy; ++i) printf("N");
  return 0;
}
