#include <bits/stdc++.h>
using namespace std;
using INT = long long;
using pii = pair<int, int>;
char s[500100];
vector<int> vec[500100], id[500100];
int mx[500100][2], mn[500100][2];
int MX[500100], MN[500100];
int main() {
  int n;
  cin >> n;
  int N = 0, nn = 0;
  for (int i = 1; i <= n; i++) {
    scanf("%s", s);
    int x = 0, y = 0;
    int m = strlen(s);
    for (int j = 0; j < m; j++) {
      if (s[j] == 'B')
        x++;
      else
        y++;
    }
    vec[x + 1].push_back(y);
    N = max(N, x + 1);
  }
  memset(mn, 0x3f, sizeof mn);
  memset(MN, 0x3f, sizeof MN);
  for (int i = 0; i < 500100; i++) MX[i] = -0x3f3f3f3f;
  for (int i = 1; i <= N; i++) {
    mx[i][0] = mx[i - 1][0];
    MX[i] = MX[i - 1];
    mn[i][0] = mn[i - 1][0];
    for (auto p : vec[i]) {
      mx[i][0] = max(mx[i][0], p);
      mn[i][0] = min(mn[i][0], p);
      MX[i] = max(MX[i], p - i);
    }
  }
  int l = 0x3f3f3f3f, r = 0;
  for (int i = N; i >= 1; i--) {
    mx[i][1] = mx[i + 1][1];
    mn[i][1] = mn[i + 1][1];
    MN[i] = MN[i + 1];
    for (auto p : vec[i]) {
      l = min(l, i);
      r = max(r, i);
      mx[i][1] = max(mx[i][1], p);
      mn[i][1] = min(mn[i][1], p);
      MN[i] = min(MN[i], p - i);
    }
  }
  int ans = 0x3f3f3f3f, A = 0, B = 0;
  for (int i = 1; i <= N; i++) {
    int L = 0, R = 0x3f3f3f3f;
    int st = max(i - l, r - i) - 1, ed = 0x3f3f3f3f, ok = 0;
    while (st + 1 < ed) {
      int md = (st + ed) >> 1;
      L = 0, R = 0x3f3f3f3f;
      L = max(L, MX[i - 1] + i - md);
      L = max(L, mx[i][1] - md);
      R = min(R, mn[i - 1][0] + md);
      R = min(R, MN[i] + i + md);
      if (L <= R) {
        ok = R;
        ed = md;
      } else
        st = md;
    }
    if (ans >= ed) {
      ans = ed;
      A = i - 1, B = ok;
    }
  }
  cout << ans << endl;
  for (int i = 1; i <= A; i++) printf("B");
  for (int i = 1; i <= B; i++) printf("N");
  cout << endl;
  return 0;
}
