#include <bits/stdc++.h>
using namespace std;
using P = pair<long long, long long>;
using ll = long long;
const long long INF = LLONG_MAX / 3;
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
struct UnionFind {
  std::vector<long long> par, siz;
  void init(long long n) {
    par.resize(n);
    for (long long i = 0; i < n; i++) par[i] = i;
    siz.resize(n, 1);
  }
  UnionFind(long long n) { init(n); }
  long long root(long long n) {
    if (par[n] == n)
      return n;
    else
      return par[n] = root(par[n]);
  }
  bool issame(long long x, long long y) { return (root(x) == root(y)); }
  bool marge(long long a, long long b) {
    if (issame(a, b))
      return false;
    else {
      a = root(a), b = root(b);
      if (siz[a] < siz[b]) swap(a, b);
      siz[b] += siz[a];
      par[a] = par[b];
      return true;
    }
  }
  long long size(long long n) { return siz[root(n)]; }
};
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long lcm(long long i, long long j) { return i * (j / gcd(i, j)); }
const long long MOD = 998244353;
long long fac[510000], finv[510000], inv[510000];
long long MAX = 510000;
bool COMinited = false;
long long COM(long long n, long long k) {
  if (COMinited == false) {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (long long i = 2; i < MAX; i++) {
      fac[i] = fac[i - 1] * i % MOD;
      inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
      finv[i] = finv[i - 1] * inv[i] % MOD;
    }
    COMinited = true;
  }
  if (n < k) return 0;
  if (n < 0 || k < 0) return 0;
  return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}
long long modpow(long long a, long long n, long long mod) {
  long long res = 1;
  while (n > 0) {
    if (n & 1) res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}
long long modinv(long long a, long long mod) { return modpow(a, mod - 2, mod); }
template <typename T>
struct BinaryIndexedTree {
  vector<T> data;
  BinaryIndexedTree(long long sz) { data.assign(++sz, 0); }
  T sum(long long k) {
    T ret = 0;
    for (++k; k > 0; k -= k & -k) ret += data[k];
    return (ret);
  }
  void add(long long k, T x) {
    for (++k; k < data.size(); k += k & -k) data[k] += x;
  }
};
signed main() {
  long long n;
  cin >> n;
  vector<string> dp[10];
  dp[0].push_back("a");
  for (long long i = (long long)1, i_len = (n); i < i_len; i++) {
    for (long long j = (long long)0, j_len = (dp[i - 1].size()); j < j_len;
         j++) {
      for (long long k = (long long)0,
                     k_len = (dp[i - 1][j][dp[i - 1][j].size() - 1] - 'a' + 2);
           k < k_len; k++) {
        char ch = (char)('a' + k);
        std::string s{ch};
        dp[i].push_back(dp[i - 1][j] + s);
      }
    }
  }
  sort(dp[n - 1].begin(), dp[n - 1].end());
  for (long long i = (long long)0, i_len = (dp[n - 1].size()); i < i_len; i++) {
    cout << dp[n - 1][i] << endl;
  }
}
