#include <bits/stdc++.h>
int main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  int n;
  std::cin >> n;
  std::vector<int> a(n), b(n);
  for (int i = 0; i < n; ++i) {
    std::string s;
    std::cin >> s;
    a[i] = std::count(s.begin(), s.end(), 'B');
    b[i] = s.length() - a[i];
  }
  auto solve = [&](int m) {
    int xMin = 0, xMax = 1e9, yMin = 0, yMax = 1e9, dMin = -1e9, dMax = 1e9;
    for (int i = 0; i < n; ++i) {
      xMin = std::max(xMin, a[i] - m);
      xMax = std::min(xMax, a[i] + m);
      yMin = std::max(yMin, b[i] - m);
      yMax = std::min(yMax, b[i] + m);
      dMin = std::max(dMin, a[i] - b[i] - m);
      dMax = std::min(dMax, a[i] - b[i] + m);
    }
    if (xMin > xMax || yMin > yMax || dMin > dMax || xMin - yMax > dMax ||
        xMax - yMin < dMin)
      return std::make_pair(-1, -1);
    int x, y;
    if (xMin - yMax >= dMin) {
      x = xMin;
      y = yMax;
    } else if (xMax - yMax >= dMin) {
      y = yMax;
      x = dMin + y;
    } else {
      x = xMax;
      y = x - dMin;
    }
    return std::make_pair(x, y);
  };
  int l = 0, r = 5e5;
  while (l < r) {
    int m = (l + r) / 2;
    auto [x, y] = solve(m);
    if (x != -1) {
      r = m;
    } else {
      l = m + 1;
    }
  }
  auto [x, y] = solve(l);
  std::cout << l << "\n";
  std::cout << std::string(x, 'B') + std::string(y, 'N') << "\n";
  return 0;
}
