#include <bits/stdc++.h>
using ll = long long;
const ll MOD = 998244353;
const int INF = (ll)1e9 + 7;
const ll INFLL = (ll)1e18;
using namespace std;
template <class t>
using vvector = vector<vector<t>>;
template <class t>
using vvvector = vector<vector<vector<t>>>;
template <class t>
using priority_queuer = priority_queue<t, vector<t>, greater<t>>;
template <class t, class u>
bool chmax(t &a, u b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class t, class u>
bool chmin(t &a, u b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
ll modpow(ll x, ll b) {
  ll res = 1;
  while (b) {
    if (b & 1) res = res * x % MOD;
    x = x * x % MOD;
    b >>= 1;
  }
  return res;
}
ll modinv(ll x) { return modpow(x, MOD - 2); }
bool was_output = false;
template <class t>
void output(t a) {
  if (was_output) cout << " ";
  cout << a;
  was_output = true;
}
void outendl() {
  was_output = false;
  cout << endl;
}
ll in() {
  ll res;
  scanf("%lld", &res);
  return res;
}
template <class t>
istream &operator>>(istream &is, vector<t> &x) {
  for (auto &i : x) is >> i;
  return is;
}
template <class t, class u>
istream &operator>>(istream &is, pair<t, u> &x) {
  is >> x.first >> x.second;
  return is;
}
template <class t>
void in(t &x) {
  cin >> x;
}
int n;
vector<int> sum;
void out() {
  for (int i = (n) * (strlen("") != 0); i < (int)(strlen("") ?: (n)); ++i) {
    cout << (char)('a' + sum[i]);
  }
  cout << endl;
}
void func(int place) {
  if (place == n) {
    out();
    return;
  }
  for (int i = (place + 1) * (strlen("") != 0);
       i < (int)(strlen("") ?: (place + 1)); ++i) {
    sum[i] = i;
    func(place + 1);
  }
}
int main() {
  n = in();
  sum.resize(n);
  func(0);
  return 0;
}
