#include <bits/stdc++.h>
using ll = long long;
using namespace std;
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
int INF = 1e9 + 5;
bool outside(int cornerx, int cornery, int c, int minx, int maxx, int miny,
             int maxy, int mind, int maxd) {
  return cornerx <= minx && cornery <= miny && cornery + c - cornerx >= maxd &&
         cornery - c - cornerx <= mind && cornerx + 2 * c >= maxx &&
         cornery + 2 * c >= maxy;
}
int binsearch(int x, int y, int xmul, int ymul, int minx, int maxx, int miny,
              int maxy, int mind, int maxd) {
  int left = 0, right = 1e7;
  while (left < right) {
    int mid = left + (right - left) / 2;
    int cornerx = x + xmul * mid, cornery = y + ymul * mid;
    if (outside(cornerx, cornery, mid, minx, maxx, miny, maxy, mind, maxd)) {
      right = mid;
    } else {
      left = mid + 1;
    }
  }
  if (left == 12) {
    ;
  }
  return left;
}
void solve() {
  int n;
  cin >> n;
  int minx = INF, maxx = -INF, miny = INF, maxy = -INF, mind = INF, maxd = -INF;
  for (int i = 0; i < n; i++) {
    string s;
    cin >> s;
    int b = 0, n = 0;
    for (char c : s) {
      if (c == 'B')
        b++;
      else
        n++;
    };
    minx = min(minx, b);
    maxx = max(maxx, b);
    miny = min(miny, n);
    maxy = max(maxy, n);
    mind = min(mind, n - b);
    maxd = max(maxd, n - b);
  };
  int ans = INF;
  int x, y;
  for (int i = -2e5; i <= 2e5; i++) {
    int a = binsearch(minx, miny + i, 0, 0, minx, maxx, miny, maxy, mind, maxd);
    if (a < ans) {
      ans = a;
      x = minx;
      y = miny + i;
    }
  }
  for (int i = -2e5; i <= 2e5; i++) {
    int a = binsearch(minx + i, maxd + minx + i, 0, -1, minx, maxx, miny, maxy,
                      mind, maxd);
    if (a < ans) {
      ans = a;
      x = minx + i;
      y = maxd + minx + i - ans;
    }
  }
  for (int i = -2e5; i <= 2e5; i++) {
    int a =
        binsearch(maxx + i, maxy, -1, -2, minx, maxx, miny, maxy, mind, maxd);
    ans = min(ans, a);
    if (a < ans) {
      ans = a;
      x = maxx + i - ans;
      y = maxy - 2 * ans;
    }
  }
  for (int i = -2e5; i <= 2e5; i++) {
    int a =
        binsearch(maxx, maxy + i, -2, -2, minx, maxx, miny, maxy, mind, maxd);
    if (a < ans) {
      ans = a;
      x = maxx - 2 * ans;
      y = maxy + i - 2 * ans;
    }
  }
  for (int i = -2e5; i <= 2e5; i++) {
    int a = binsearch(maxx + i, mind + maxx + i, -2, -1, minx, maxx, miny, maxy,
                      mind, maxd);
    ans = min(ans, a);
    if (a < ans) {
      ans = a;
      x = maxx + i - 2 * ans;
      y = mind + maxx + i - ans;
    }
  }
  for (int i = -2e5; i <= 2e5; i++) {
    int a =
        binsearch(minx + i, miny, -1, 0, minx, maxx, miny, maxy, mind, maxd);
    if (a < ans) {
      ans = a;
      x = minx + i - ans;
      y = miny;
    }
  };
  cout << ans << endl;
  string out = "";
  for (int i = 0; i < ans + x; i++) out += 'B';
  for (int i = 0; i < ans + y; i++) out += 'N';
  cout << out << endl;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  solve();
  return 0;
}
