#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll LINF = 1001002003004005006ll;
int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
template <class T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return true;
  }
  return false;
}
signed main() {
  cin.tie(0);
  ios::sync_with_stdio(0);
  int n;
  cin >> n;
  for (int bit = 0; bit < (1 << (n - 1)); bit++) {
    string s = "";
    int cnt = __builtin_popcount(bit);
    for (int i = 0; i < n; i++) {
      if ((bit >> i) & 1) {
        s.push_back('a' + cnt);
        cnt--;
      } else {
        s.push_back('a');
      }
    }
    reverse(s.begin(), s.end());
    cout << s << endl;
  }
  return 0;
}
