#include <bits/stdc++.h>
const int N = 5e5 + 5, inf = 1e9 + 7;
using namespace std;
char s[N];
bool flag;
int n, ansa, ansb, a[N], b[N];
int Ll, Lr, Rl, Rr;
struct node {
  int a, b;
} c[N];
bool cmp(node a, node b) { return a.a < b.a; }
void putll(node a, int val, int mid) {
  int x = a.b - mid;
  Ll = max(Ll, x);
}
void putlr(node a, int val, int mid) {
  int x = a.b + mid - a.a;
  Lr = min(Lr, x);
}
void putrl(node a, int val, int mid) {
  int x = a.b - mid - a.a;
  Rl = max(Rl, x);
}
void putrr(node a, int val, int mid) {
  int x = a.b + mid;
  Rr = min(Rr, x);
}
void update(int i) {
  int l = 0, r = inf;
  l = max(l, Ll);
  l = max(l, Rl + i);
  r = min(r, Lr + i);
  r = min(r, Rr);
  if (l <= r && (i + r) > 0) {
    flag = true;
    ansa = i;
    ansb = r;
  }
}
bool chk(int k) {
  Ll = -inf, Rl = -inf, Lr = inf, Rr = inf;
  int lx = 0, rx = inf;
  for (int i = 1; i <= n; ++i) c[i].a = a[i], c[i].b = b[i];
  for (int i = 1; i <= n; ++i)
    lx = max(lx, c[i].a - k), rx = min(rx, c[i].a + k);
  sort(c + 1, c + n + 1, cmp);
  for (int i = 1; i <= n; ++i) putll(c[i], 1, k), putlr(c[i], 1, k);
  int top = 1;
  flag = false;
  for (int i = lx; i <= rx; ++i) {
    for (; top <= n && c[top].a <= i; ++top)
      putrl(c[top], 1, k), putrr(c[top], 1, k);
    update(i);
  }
  return flag;
}
int main() {
  scanf("%d", &n);
  int mxa = 0, mxb = 0;
  for (int i = 1; i <= n; ++i) {
    scanf("%s", s + 1);
    int sz = strlen(s + 1);
    a[i] = b[i] = 0;
    for (int j = 1; j <= sz; ++j)
      if (s[j] == 'N')
        ++a[i];
      else
        ++b[i];
    mxa = max(mxa, a[i]);
    mxb = max(mxb, b[i]);
  }
  int res = inf, l = 0, r = mxa + mxb;
  for (; l <= r;) {
    int mid = (l + r) / 2;
    if (chk(mid))
      res = mid, r = mid - 1;
    else
      l = mid + 1;
  }
  printf("%d\n", res);
  for (int i = 1; i <= ansa; ++i) putchar('N');
  for (int i = 1; i <= ansb; ++i) putchar('B');
  puts("");
  return 0;
}
