#include <bits/stdc++.h>
using namespace std;
using pi = pair<int, int>;
using lint = long long;
const int MAXN = 500005;
vector<pi> v;
pi ans;
bool trial(int T) {
  int sx = 0, ex = 1e9;
  int sy = 0, ey = 1e9;
  int sa = -1e9, ea = 1e9;
  for (auto &[x, y] : v) {
    sx = max(sx, x - T);
    ex = min(ex, x + T);
    sy = max(sy, y - T);
    ey = min(ey, y + T);
    sa = max(sa, x - y - T);
    ea = min(ea, x - y + T);
  }
  for (int i = sx; i <= ex; i++) {
    int t = max(sy, i - ea), u = min(ey, i - sa);
    if (i == 0) t = max(t, 1);
    if (t <= u) {
      ans = pi(i, t);
      return 1;
    }
  }
  return 0;
}
char buf[MAXN];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%s", buf);
    int l = strlen(buf);
    int x = count(buf, buf + l, 'B');
    int y = count(buf, buf + l, 'N');
    v.emplace_back(x, y);
  }
  int s = 0, e = 1e6;
  while (s != e) {
    int m = (s + e) / 2;
    if (trial(m))
      e = m;
    else
      s = m + 1;
  }
  trial(s);
  cout << s << endl;
  for (int i = 0; i < ans.first; i++) putchar('B');
  for (int i = 0; i < ans.second; i++) putchar('N');
  puts("");
}
