#include <bits/stdc++.h>
long long read() {
  long long 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 * 10 + c - '0';
    c = getchar();
  }
  return f * x;
}
long long max(long long a, long long b) { return a > b ? a : b; }
long long min(long long a, long long b) { return a < b ? a : b; }
void umax(long long& a, long long t) {
  if (t > a) a = t;
}
bool umin(long long& a, long long t) {
  if (t < a) return a = t, 1;
  return 0;
}
const long long INF = 1ll << 50;
char s[500011];
long long cn[500011], cb[500011], n, maxl;
long long f(long long nown, long long nowb) {
  if (nown + nowb == 0) return 1e18;
  long long res = 0;
  for (int i = 1; i <= n; ++i) {
    if (nown >= cn[i]) {
      if (nowb >= cb[i])
        umax(res, max(nown - cn[i], nowb - cb[i]));
      else
        umax(res, (nown - cn[i]) + (cb[i] - nowb));
    } else {
      if (nowb >= cb[i])
        umax(res, (cn[i] - nown) + (nowb - cb[i]));
      else
        umax(res, max(cn[i] - nown, cb[i] - nowb));
    }
  }
  return res;
}
long long g(long long nown, bool flag = 0) {
  long long l = 0, r = maxl;
  while (r - l > 3) {
    long long mid1 = (l + r - 1) >> 1, mid2 = mid1 + 2;
    if (f(nown, mid1) < f(nown, mid2))
      r = mid2;
    else
      l = mid1;
  }
  long long res = f(nown, l);
  for (int i = l + 1; i <= r; ++i) umin(res, f(nown, i));
  if (flag) {
    for (int i = l; i <= r; ++i)
      if (f(nown, i) == res) {
        for (int j = 1; j <= i; ++j) putchar('B');
        break;
      }
  }
  return res;
}
int main() {
  n = read();
  for (int i = 1; i <= n; ++i) {
    scanf("%s", s + 1);
    long long l = strlen(s + 1);
    for (int j = 1; j <= l; ++j)
      if (s[j] == 'N')
        ++cn[i];
      else
        ++cb[i];
    umax(maxl, l);
  }
  long long l = 0, r = maxl;
  while (r - l > 3) {
    long long mid1 = (l + r - 1) >> 1, mid2 = mid1 + 2;
    if (g(mid1) < g(mid2))
      r = mid2;
    else
      l = mid1;
  }
  long long res = g(l);
  for (int i = l + 1; i <= r; ++i) umin(res, g(i));
  printf("%lld\n", res);
  for (int i = l; i <= r; ++i)
    if (g(i) == res) {
      for (int j = 1; j <= i; ++j) putchar('N');
      g(i, 1);
      return 0;
    }
  return 0;
}
