#include <bits/stdc++.h>
const int MAXN = 5e5 + 19;
int n;
char s[MAXN];
int lx = 1e9, ly = 1e9, lb = 1e9, rx = -1e9, ry = -1e9, rb = -1e9;
int X, Y;
bool check(int v) {
  int xL = rx - v, xR = lx + v, yL = ry - v, yR = ly + v;
  if (xL > xR || yL > yR) return 0;
  int bL = yL - xR, bR = yR - xL;
  if (rb - lb > 2 * v) return 0;
  if (lb + v < bL || rb - v > bR) return 0;
  int b = std::max(bL, rb - v);
  X = xR, Y = xR + b;
  if (Y > yR) X += yR - Y, Y += yR - Y;
  return 1;
}
int main() {
  std::scanf("%d", &n);
  for (int i = 1; i <= n; ++i) {
    std::scanf("%s", s);
    int len = std::strlen(s);
    int x = 0, y = 0;
    for (int j = 0; j < len; ++j)
      if (s[j] == 'B')
        ++x;
      else
        ++y;
    lx = std::min(lx, x), ly = std::min(ly, y), lb = std::min(lb, y - x);
    rx = std::max(rx, x), ry = std::max(ry, y), rb = std::max(rb, y - x);
  }
  int l = 0, r = 1e9;
  while (l < r) {
    int mid = (l + r) >> 1;
    if (check(mid))
      r = mid;
    else
      l = mid + 1;
  }
  std::printf("%d\n", l);
  for (int i = 1; i <= X; ++i) std::putchar('B');
  for (int i = 1; i <= Y; ++i) std::putchar('N');
}
