#include <bits/stdc++.h>
const int MAXN = 5e5 + 5;
int x[MAXN], y[MAXN];
int n;
char str[MAXN];
int ansx, ansy;
inline bool chk(int k) {
  int lx = 0, rx = 1e9, ly = 0, ry = 1e9, lxy = -1e9, rxy = 1e9;
  ansx = ansy = -1;
  for (int i = 1; i <= n; ++i)
    lx = std::max(lx, x[i] - k), rx = std::min(rx, x[i] + k),
    ly = std::max(ly, y[i] - k), ry = std::min(ry, y[i] + k),
    lxy = std::max(lxy, x[i] - y[i] - k), rxy = std::min(rxy, x[i] - y[i] + k);
  if (lx <= rx && ly <= ry && lxy <= rxy) {
    int ll = lx - ry, rr = rx - ly;
    for (int y = ly; y <= ry; ++y) {
      int llx = std::max({lx, lxy + y, ll + y}),
          rrx = std::min({rx, rxy + y, rr + y});
      if (llx <= rrx && (y || rrx > 0)) {
        ansx = rrx;
        ansy = y;
        return 1;
      }
    }
  }
  return 0;
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) {
    scanf("%s", str + 1);
    int len = strlen(str + 1);
    for (int j = 1; j <= len; ++j) {
      if (str[j] == 'B')
        x[i]++;
      else
        y[i]++;
    }
  }
  int l = 0, r = 500000 + 5, ans = -1;
  while (l <= r) {
    int mid = (l + r) >> 1;
    if (chk(mid))
      ans = mid, r = mid - 1;
    else
      l = mid + 1;
  }
  printf("%d\n", ans);
  chk(ans);
  for (int i = 1; i <= ansx; ++i) putchar('B');
  for (int i = 1; i <= ansy; ++i) putchar('N');
  puts("");
  return 0;
}
