#include <bits/stdc++.h>
using namespace std;
int n, a[500005], b[500005];
char s[500005];
int res = 1e9, xx, yy;
int calc2(int x, int y) {
  if (x == 0 && y == 0) return 1000000000;
  int ans = 0;
  for (int i = 1; i <= n; i++) {
    if (x <= a[i] && y <= b[i])
      ans = max(ans, max(a[i] - x, b[i] - y));
    else if (x <= a[i] || y <= b[i])
      ans = max(ans, abs(a[i] - x) + abs(b[i] - y));
    else
      ans = max(ans, max(x - a[i], y - b[i]));
  }
  if (ans < res) {
    res = ans;
    xx = x, yy = y;
  }
  return ans;
}
int calc1(int x) {
  int l = 0, r = 500000;
  if (x == 0) l = 1;
  while (l <= r) {
    int mid = (l + r) >> 1;
    if (calc2(x, mid) < calc2(x, mid + 1))
      r = mid - 1;
    else
      l = mid + 1;
  }
  return min(calc2(x, l), calc2(x, r));
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%s", s + 1);
    int x = (int)strlen(s + 1);
    for (int j = 1; j <= x; j++) {
      if (s[j] == 'N')
        a[i]++;
      else
        b[i]++;
    }
  }
  int l = 0, r = 500000;
  while (l <= r) {
    int mid = (l + r) >> 1;
    int v1 = calc1(mid), v2 = calc1(mid + 1);
    if (v1 < v2)
      r = mid - 1;
    else if (v1 > v2)
      l = mid + 1;
    else {
      int v3 = calc1(mid + 2);
      if (v1 < v3)
        r = mid - 1;
      else if (v1 > v3)
        l = mid + 1;
      else
        break;
    }
  }
  printf("%d\n", res);
  for (int i = 1; i <= xx; i++) putchar('N');
  for (int i = 1; i <= yy; i++) putchar('B');
  printf("\n");
  return 0;
}
