#include <bits/stdc++.h>
using namespace std;
struct Hexagon {
  int xl, xr;
  int yl, yr;
  int xyl, xyr;
  Hexagon(int xl = -(1 << 29), int xr = (1 << 29), int yl = -(1 << 29),
          int yr = (1 << 29), int xyl = -(1 << 29), int xyr = (1 << 29))
      : xl(xl), xr(xr), yl(yl), yr(yr), xyl(xyl), xyr(xyr) {}
};
Hexagon intersection(Hexagon a, Hexagon b) {
  return Hexagon(max(a.xl, b.xl), min(a.xr, b.xr), max(a.yl, b.yl),
                 min(a.yr, b.yr), max(a.xyl, b.xyl), min(a.xyr, b.xyr));
}
vector<pair<long long, long long> > points;
char s[550000];
pair<long long, long long> ok_str;
bool ok(int t) {
  Hexagon hex;
  for (auto p : points) {
    int x = p.first, y = p.second;
    auto tmp = Hexagon(x - t, x + t, y - t, y + t, x - y - t, x - y + t);
    hex = intersection(tmp, hex);
  }
  if (hex.xl > hex.xr) return false;
  if (hex.yl > hex.yr) return false;
  if (hex.xyl > hex.xyr) return false;
  int xyl = hex.xl - hex.yr;
  int xyr = hex.xr - hex.yl;
  if (xyr < hex.xyl || hex.xyr < xyl) return false;
  int xy = min(xyr, hex.xyr);
  int xr = xy + hex.yr;
  int x = min(xr, hex.xr);
  int y = x - xy;
  ok_str = {x, y};
  return true;
}
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%s", s);
    int bcnt = 0, ncnt = 0;
    int l = strlen(s);
    for (int i = 0; i < l; i++) {
      if (s[i] == 'B')
        bcnt++;
      else
        ncnt++;
    }
    points.emplace_back(ncnt, bcnt);
  }
  sort(points.begin(), points.end());
  points.erase(unique(points.begin(), points.end()), points.end());
  int bottom = 0, top = 1000000;
  if (points.size() == 1) top = 0;
  while (top - bottom > 1) {
    int mid = (top + bottom) / 2;
    if (ok(mid))
      top = mid;
    else
      bottom = mid;
  }
  ok(top);
  cout << top << endl;
  for (int i = 0; i < ok_str.first; i++) cout << 'N';
  for (int i = 0; i < ok_str.second; i++) cout << 'B';
  cout << endl;
  return 0;
}
