#include <bits/stdc++.h>
using namespace std;
const int N = 5e5 + 10;
char s[N];
int n;
pair<int, int> a[N];
bool check(int ub, int db, int uy, int dy, int ux, int dx, pair<int, int> a) {
  if (!a.first && !a.second) return 0;
  return dx <= a.first && a.first <= ux && dy <= a.second && a.second <= uy &&
         db + a.first <= a.second && a.second <= ub + a.first;
}
pair<int, pair<int, int> > check(int len) {
  int ub = 1e9, db = -1e9, uy = 1e9, dy = 1, ux = 1e9, dx = -1e9;
  for (int i = 1; i <= n; i++) {
    ub = min(ub, a[i].second - a[i].first + len);
    db = max(db, a[i].second - a[i].first - len);
    uy = min(uy, a[i].second + len);
    dy = max(dy, a[i].second - len);
    ux = min(ux, a[i].first + len);
    dx = max(dx, a[i].first - len);
  }
  if (check(ub, db, uy, dy, ux, dx, {dx, dy})) return {1, {dx, dy}};
  if (check(ub, db, uy, dy, ux, dx, {ux, uy})) return {1, {ux, uy}};
  if (check(ub, db, uy, dy, ux, dx, {ux, dy})) return {1, {ux, dy}};
  if (check(ub, db, uy, dy, ux, dx, {dx, uy})) return {1, {dx, uy}};
  if (check(ub, db, uy, dy, ux, dx, {dx, dx + ub})) return {1, {dx, dx + ub}};
  if (check(ub, db, uy, dy, ux, dx, {dx, dx + db})) return {1, {dx, dx + db}};
  if (check(ub, db, uy, dy, ux, dx, {ux, ux + ub})) return {1, {ux, ux + ub}};
  if (check(ub, db, uy, dy, ux, dx, {ux, ux + db})) return {1, {ux, ux + db}};
  if (check(ub, db, uy, dy, ux, dx, {dy - db, dy})) return {1, {dy - db, dy}};
  if (check(ub, db, uy, dy, ux, dx, {dy - ub, dy})) return {1, {dy - ub, dy}};
  if (check(ub, db, uy, dy, ux, dx, {uy - db, uy})) return {1, {uy - db, uy}};
  if (check(ub, db, uy, dy, ux, dx, {uy - ub, uy})) return {1, {uy - ub, uy}};
  ub = 1e9, db = -1e9, uy = 1e9, dy = -1e9, ux = 1e9, dx = 1;
  for (int i = 1; i <= n; i++) {
    ub = min(ub, a[i].second - a[i].first + len);
    db = max(db, a[i].second - a[i].first - len);
    uy = min(uy, a[i].second + len);
    dy = max(dy, a[i].second - len);
    ux = min(ux, a[i].first + len);
    dx = max(dx, a[i].first - len);
  }
  if (check(ub, db, uy, dy, ux, dx, {dx, dy})) return {1, {dx, dy}};
  if (check(ub, db, uy, dy, ux, dx, {ux, uy})) return {1, {ux, uy}};
  if (check(ub, db, uy, dy, ux, dx, {ux, dy})) return {1, {ux, dy}};
  if (check(ub, db, uy, dy, ux, dx, {dx, uy})) return {1, {dx, uy}};
  if (check(ub, db, uy, dy, ux, dx, {dx, dx + ub})) return {1, {dx, dx + ub}};
  if (check(ub, db, uy, dy, ux, dx, {dx, dx + db})) return {1, {dx, dx + db}};
  if (check(ub, db, uy, dy, ux, dx, {ux, ux + ub})) return {1, {ux, ux + ub}};
  if (check(ub, db, uy, dy, ux, dx, {ux, ux + db})) return {1, {ux, ux + db}};
  if (check(ub, db, uy, dy, ux, dx, {dy - db, dy})) return {1, {dy - db, dy}};
  if (check(ub, db, uy, dy, ux, dx, {dy - ub, dy})) return {1, {dy - ub, dy}};
  if (check(ub, db, uy, dy, ux, dx, {uy - db, uy})) return {1, {uy - db, uy}};
  if (check(ub, db, uy, dy, ux, dx, {uy - ub, uy})) return {1, {uy - ub, uy}};
  return {0, {0, 0}};
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%s", s);
    int len = strlen(s);
    for (int j = 0; j < len; j++)
      if (s[j] == 'B')
        a[i].first++;
      else
        a[i].second++;
  }
  int l = 0, r = 1000000, mid, s = 1000000;
  while (l <= r) {
    if (check(mid = (l + r) / 2).first)
      s = min(s, mid), r = mid - 1;
    else
      l = mid + 1;
  }
  printf("%d\n", s);
  auto u = check(s);
  int x = 0;
  int y = 0;
  x = u.second.first;
  y = u.second.second;
  for (int i = 1; i <= x; i++) printf("B");
  for (int i = 1; i <= y; i++) printf("N");
  return 0;
}
