#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 10;
const int mod = 1e9 + 7;
int read() {
  int x = 0, f = 1;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') f = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') x = (x << 1) + (x << 3) + c - '0', c = getchar();
  return x * f;
}
struct node {
  int l, r;
};
node p[N];
node c[3];
int n, ansx, ansy;
bool check(int v) {
  for (int t = 0; t < 3; t++) c[t].l = -1e9, c[t].r = 1e9;
  c[1].l = c[0].l = 0;
  for (int i = 1; i <= n; i++) {
    int x = p[i].l, y = p[i].r;
    c[0].l = max(c[0].l, x - v);
    c[0].r = min(c[0].r, x + v);
    c[1].l = max(c[1].l, y - v);
    c[1].r = min(c[1].r, y + v);
    c[2].l = max(c[2].l, x - y - v);
    c[2].r = min(c[2].r, x - y + v);
  }
  for (int t = 0; t < 3; t++)
    if (c[t].r < c[t].l) return 0;
  int l = c[0].l - c[1].r;
  int r = c[0].r - c[1].l;
  if (max(c[2].l, l) <= min(c[2].r, r)) {
    int k = max(c[2].l, l);
    int ls = max(c[0].l, c[1].l + k), rs = min(c[0].r, c[1].r + k);
    if (ls <= rs) {
      ansx = rs;
      ansy = rs - k;
    }
    return 1;
  } else
    return 0;
}
char s[N];
int main() {
  n = read();
  for (int i = 1; i <= n; i++) {
    scanf("%s", s);
    int len = strlen(s);
    for (int j = 0; j < len; j++) {
      if (s[j] == 'B')
        p[i].l++;
      else
        p[i].r++;
    }
  }
  int l = 0, r = 1e6, ans = r;
  while (l <= r) {
    int mid = (l + r) >> 1;
    if (check(mid)) {
      ans = mid;
      r = mid - 1;
    } else
      l = mid + 1;
  }
  cout << ans << endl;
  cout << string(ansx, 'B') + string(ansy, 'N') << endl;
}
