#include <bits/stdc++.h>
using namespace std;
const long long maxn = 2e5 + 5;
pair<bool, pair<long long, long long> > check(
    vector<pair<long long, long long> > a, long long k) {
  long long ma1 = 1e18;
  long long mi1 = 0;
  long long ma2 = 1e18;
  long long mi2 = 0;
  long long mar = 1e18;
  long long mir = (-1e18);
  for (long long i = 0; i < a.size(); ++i) {
    ma1 = min(ma1, a[i].first + k);
    mi1 = max(mi1, a[i].first - k);
    ma2 = min(ma2, a[i].second + k);
    mi2 = max(mi2, a[i].second - k);
    mar = min(mar, a[i].first - a[i].second + k);
    mir = max(mir, a[i].first - a[i].second - k);
  }
  if (ma1 < mi1 || ma2 < mi2 || mar < mir) {
    return {false, {-1, -1}};
  }
  for (long long i = mi1; i <= ma1; ++i) {
    long long x = i;
    long long y = mi2;
    if ((x - y) >= mir && (x - y) <= mar && (x + y) != 0) {
      return {true, {x, y}};
    }
  }
  for (long long i = mi1; i <= ma1; ++i) {
    long long x = i;
    long long y = ma2;
    if ((x - y) >= mir && (x - y) <= mar && (x + y) != 0) {
      return {true, {x, y}};
    }
  }
  for (long long i = mi2; i <= ma2; ++i) {
    long long x = mi1;
    long long y = i;
    if ((x - y) >= mir && (x - y) <= mar && (x + y) != 0) {
      return {true, {x, y}};
    }
  }
  for (long long i = mi2; i <= ma2; ++i) {
    long long x = ma1;
    long long y = i;
    if ((x - y) >= mir && (x - y) <= mar && (x + y) != 0) {
      return {true, {x, y}};
    }
  }
  return {false, {-1, -1}};
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long n;
  cin >> n;
  vector<pair<long long, long long> > a(n);
  for (long long i = 0; i < n; ++i) {
    string s;
    cin >> s;
    pair<long long, long long> curr = {0, 0};
    for (long long j = 0; j < s.size(); ++j) {
      if (s[j] == 'B') {
        curr.first++;
      } else {
        curr.second++;
      }
    }
    a[i] = curr;
  }
  long long low = (-1);
  long long up = 1e6;
  pair<long long, long long> res;
  while (true) {
    if ((up - low) == 1) {
      cout << up << endl;
      for (long long i = 0; i < res.first; ++i) {
        cout << 'B';
      }
      for (long long i = 0; i < res.second; ++i) {
        cout << 'N';
      }
      exit(0);
    }
    long long k = (low + up) / 2;
    pair<bool, pair<long long, long long> > o = check(a, k);
    if (o.first) {
      res = o.second;
      up = k;
    } else {
      low = k;
    }
  }
  return 0;
}
