#include <bits/stdc++.h>
using namespace std;
int n, a[300001], b[300001], ans, maxn[3], minn[3];
inline bool check(int x) {
  maxn[0] = maxn[1] = maxn[2] = 1 << 30;
  minn[0] = minn[1] = 0;
  minn[2] = -1 << 30;
  for (register int i = 1; i <= n; ++i) {
    minn[0] = max(minn[0], a[i] - x);
    maxn[0] = min(maxn[0], a[i] + x);
    minn[1] = max(minn[1], b[i] - x);
    maxn[1] = min(maxn[1], b[i] + x);
    minn[2] = max(minn[2], a[i] - b[i] - x);
    maxn[2] = min(maxn[2], a[i] - b[i] + x);
  }
  if (minn[0] > maxn[0] || minn[1] > maxn[1] || minn[2] > maxn[2] ||
      max(minn[1], minn[0] - maxn[2]) > min(maxn[1], maxn[0] - minn[2]))
    return 0;
  return 1;
}
int main() {
  scanf("%d", &n);
  for (register int i = 1; i <= n; ++i) {
    string s;
    cin >> s;
    int len = s.length();
    for (register int j = 0; j < len; ++j)
      if (s[j] == 'B')
        ++a[i];
      else
        ++b[i];
  }
  int l = 0, r = 1e7, mid;
  while (l <= r) {
    mid = (l + r) >> 1;
    if (check(mid)) {
      r = mid - 1;
      ans = mid;
    } else
      l = mid + 1;
  }
  check(ans);
  printf("%d\n", ans);
  minn[1] = max(minn[1], minn[0] - maxn[2]);
  maxn[1] = min(maxn[1], maxn[0] - minn[2]);
  for (register int i = minn[0]; i <= maxn[0]; ++i) {
    int x = max(minn[1], i - maxn[2]), y = min(maxn[1], i - minn[2]);
    if (x > y || (i <= 0 && y <= 0)) continue;
    for (register int j = 1; j <= i; ++j) putchar('B');
    for (register int j = 1; j <= (i ? x : y); ++j) putchar('N');
    puts("");
    return 0;
  }
  return 0;
}
