#include <bits/stdc++.h>
using ll = long long;
constexpr ll mod = 1e9 + 7;
constexpr ll INF = 1LL << 60;
ll gcd(ll n, ll m) {
  ll tmp;
  while (m != 0) {
    tmp = n % m;
    n = m;
    m = tmp;
  }
  return n;
}
ll lcm(ll n, ll m) { return abs(n) / gcd(n, m) * abs(m); }
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
using namespace std;
void solve() {
  int n;
  cin >> n;
  vector<string> s(1e5);
  for (int i = (int)0; i < (int)n; ++i) {
    ll cnt = 0;
    for (int j = (int)0; j < (int)s.size(); ++j) {
      s[j] += string{char('a' + (cnt) % (i + 1))};
      cnt++;
    }
  }
  sort(s.begin(), s.end());
  s.erase(unique(s.begin(), s.end()), s.end());
  set<int> bad;
  for (int i = (int)0; i < (int)s.size(); ++i) {
    bool ng = false;
    for (int j = (int)0; j < (int)n - 1; ++j) {
      if (s[i][j + 1] - s[i][j] > 1) {
        s[i][j + 1] -= s[i][j + 1] - s[i][j];
      }
    }
    if (ng) bad.emplace(i);
  }
  sort(s.begin(), s.end());
  s.erase(unique(s.begin(), s.end()), s.end());
  for (int i = (int)0; i < (int)s.size(); ++i)
    if (!bad.count(i)) cout << s[i] << endl;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed << setprecision(15);
  solve();
  return 0;
}
