#include <bits/stdc++.h>   #pragma GCC optimize( Ofast ,  unroll-loops ,  no-stack-protector )   using namespace std;   using ll = long long;   using ld = double;   using pii = pair<int, int>;   using uint = unsigned int;   using ull = unsigned long long;   mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());   default_random_engine generator;   void solve();   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     cout << setprecision(16) << fixed;     cerr << setprecision(16) << fixed;     int tests = 1;     for (int test = 1; test <= tests; ++test) {       solve();     }   }   const int INF = 1e9;   struct Point {     int x, y;   };   void solve() {     int n;     cin >> n;     vector<Point> p(n);     for (int i = 0; i < n; ++i) {       string s;       cin >> s;       int a = 0, b = 0;       for (char c : s) {         a += c ==  B ;         b += c ==  N ;       }       p[i] = {a, b};     }     int minx = INF, maxx = -INF;     int miny = INF, maxy = -INF;     int l = INF, r = -INF;     for (auto [x, y] : p) {       minx = min(minx, x);       maxx = max(maxx, x);       miny = min(miny, y);       maxy = max(maxy, y);       l = min(l, x - y);       r = max(r, x - y);     }     int res = 0;     res = max(res, (maxx - minx + 1) / 2);     res = max(res, (maxy - miny + 1) / 2);     res = max(res, (minx - miny) - l);     res = max(res, r - (minx - miny));     Point best = {minx + res, miny + res};     for (int op = 0; op < 2; ++op) {       int xx = miny + l;       int yy = miny;       int cur = 0;       cur = max(cur, (maxx - xx + 2) / 3);       cur = max(cur, (maxy - yy + 1) / 2);       cur = max(cur, (r - l + 1) / 2);       if (cur < res && cur <= minx - xx) {         res = cur;         best = {xx + 2 * res, yy + res};         if (op) {           swap(best.x, best.y);         }       }       for (int i = 0; i < n; ++i) {         swap(p[i].x, p[i].y);       }       swap(minx, miny);       swap(maxx, maxy);       r *= -1;       l *= -1;       swap(l, r);     }     cout << res << endl;     string ans;     for (int i = 0; i < best.x; ++i) {       ans +=  B ;     }     for (int i = 0; i < best.y; ++i) {       ans +=  N ;     }     cout << ans << endl;   }   